Over the past two decades, Yemen has become a matter of interest and concern for countries in the region and around the world for a variety of different reasons. One that seems to have been underestimated, however, is the proliferation of non-state actors and their acquisition of conventional and non-conventional arms, especially following the Houthi armed rebellion, despite the mandate set by several U.N. Security Council (UNSC) resolutions. As long as weapons transfers to armed non-state actors are not adequately restricted and the monopoly of violence is not exclusively in the hands of the government, it will be impossible to build sustainable peace in Yemen.

Yemen under Chapter VII

Broadly speaking, U.N. statements and decisions on Yemen have been concerned with the progress of the political process and the humanitarian situation, but have also included punitive measures against actors and entities impeding transitional peace arrangements, most notably former President Ali Abdullah Saleh, Abdul Malik al-Houthi, and some relatives. UNSC Resolution 2216 is perhaps the most important decision because it subjected Yemen, under the provisions of Chapter VII of the U.N. Charter, to restrictions on arms flows and imposed special measures aimed at preventing the Houthis and Saleh from acquiring weapons, as per paragraph 14.

Previous U.N. reports had indicated that Yemen, chiefly due to its weak arms control measures, was a major source of light and medium weapons for armed groups in Somalia, thus making the issue a broader regional concern as well.

The forgotten paragraph of UNSCR 2216

Paragraph 14 of UNSC Resolution 2216 deserves to be examined. Not only does it lay out essential details to directly limit military action in Yemen, but it also constrains the regional military intervention indirectly, including by refraining from providing support to rebel groups — supposedly according to a formula embedded across UNSC statements and decisions: the preservation of Yemen’s unity, territorial integrity, and political system. This formula is often overlooked and abused, however.

Although this paragraph prohibits supplying, selling, or transferring arms, ammunition, or equipment, and/or providing technical or material support to the entities covered, the situation on the ground clearly shows otherwise. There was neither adequate international attention paid to the arms embargo package nor enough political will to follow up and strengthen the array of detection, prevention, enforcement, and/or compliance measures. As the conflict wore on, it became clear that arms, including those not previously in use in Yemen, continued to be transferred, distributed, and supplied to warring parties other than the recognized authority of President Abed Rabbo Mansour Hadi.

The arms of the Yemeni army

During the Cold War, the nature of Yemen’s two political regimes, their ideological divergence, and a series of short, repeated border wars made the possession of a qualitative military edge meaningful. South Yemen (the People's Democratic Republic of Yemen), which orbited the Eastern camp, was keen to possess ballistic weapons with ranges that would allow it to strike its main opponent, North Yemen (the Yemen Arab Republic). Following reunification in 1990, these weapons became the property of the Republic of Yemen and included mainly Russian-made Scud ballistic missiles with a range of 600 km (Type B and C), Tochka missiles, and surface-to-air (SAM) missiles. The Yemeni army also received North Korean Hwasong missiles, particularly in 2002.

The army had a considerable arsenal of weapons, encompassing armored vehicles, artillery batteries, tanks, anti-aircraft batteries, and Russian or Eastern warplanes, especially after Yemen’s military expenditure nearly tripled between 2000 and 2010, from $470 million to $1.45 billion. There is, however, no accurate count of its total stockpile of weapons, given the Saleh regime’s secrecy, and numbers are open to speculation.

Arms during the Houthi era

Upon taking over the capital, Sanaa, in late 2014, the Houthi militias inherited a great share of the state’s arms, thanks to their marriage of convenience with Saleh’s General People’s Congress (GPC). But with the beginning of the Saudi- and Emirati-led Arab Coalition’s military campaign, they lost air capabilities, although they retained their missiles, giving them a relative advantage over their local opponents and tactical allies.

Most importantly, their alliance with former President Saleh paved the way for the Houthis to access the modern arms supplied to specialized military and security units by the U.S. for counterterrorism purposes in the 2000s. The Americans later declared that they lost track of approximately $500 million worth of weapons in Yemen. The Houthis also captured secretive military camps and stockpiled arms after assassinating Saleh on Dec. 4, 2017.

While their ballistic missiles dated to the Soviet era, the Houthis nevertheless proved capable of surprising their opponents with their evolving military capabilities, reportedly shooting down modern combat or espionage military aircraft and even deploying anti-vehicle and anti-armor Kornet missiles. This surprise extended to the Houthis’ use of long-range missiles capable of reaching the Saudi capital, Riyadh, in the north, as well as their frequent use of drones (such as the Qasef) that weren’t part of the Yemeni army’s assets.

The Houthis’ cheap but technologically advanced weapons

Relying on what they had looted from the army, the Houthis developed the Qaher, Zelzal, and Borkan missiles, a set of modified missiles that could be deployed from mobile platforms and/or converted from SAM to surface-to-surface missiles, according to many reports, including those from the U.N. This is in addition to their announced development of naval arms to counter military forces at sea, either using al-Mandab-1 missiles (thought to be C-801 or C-802) or booby-trapped fast boats.

If the Houthis were less successful on the maritime front, the same cannot be said of their use of missiles: As of June 2020, they had fired a total of 312 ballistic missiles on Saudi territory, including those with a range of more than 1,000 km. They have also used a large number of short- and medium-range missiles and modified them, taking advantage of the workshops, manufacturing, and military maintenance facilities that belonged to the Yemeni army. This allowed them to direct considerable firepower within the country as well: As of 2020, the city of Marib alone had been hit by at least 112 ballistic missiles fired by the Houthis.

Furthermore, the Houthis have also intensified their use of drones, reportedly targeting Saudi Arabia with at least 400. The adoption of drones allowed the insurgents to target high-value Yemeni officials; the Houthi targeting and killing of Maj. Gen. Saleh al-Zandani, the deputy chief of staff, during a 2019 military graduation at al-Anad Air Base in Lahj is a case in point. Reconnaissance or booby-trapped drones and equipment are often purchased cheaply online and modified, including from China, making Beijing an indirect actor in the drone file.

The role of the UAE

The UAE has reportedly armed, trained, financed, and managed more than 90,000 individuals under organized structures in the eastern, western, and southern parts of the country. Militants with the UAE-backed Southern Transitional Council (STC), who looted medium and heavy arms from the 4th Military Region during the August 2019 coup d’état in Aden, reportedly used drones in the sporadic firefight in Abyan governorate, at times allowing the group to target government forces in different ways. While further details have not yet been made public, the UAE’s transfer of U.S.-made thermal missiles to STC-aligned forces, which were recorded being used in Abyan, suggests that additional transfers are highly likely.

Alongside regular arms shipments from the UAE, the unmonitored influx of weapons raises serious concerns about the spread of conventional and non-conventional foreign-made arms transferred to entities other than the Yemeni Armed Forces, in contravention of the U.N. arms embargo, including by U.S. partners. This is why Amnesty International, for instance, expressed grave concern over weapons “being passed on to completely unaccountable Coalition-allied militias.” These include U.S., French, Finnish, and South African-made tanks and armored vehicles, such as G6 Rhinos, Patria AMVs, Leclerc tanks, Oshkosh M-ATVs, and BAE Caimans, supplied to the UAE and then diverted to the Joint Forces as well as the Security Belt and other regional elite forces in the southern and eastern regions — all of which operate outside the government’s command-and-control structures.

Such diversion of Western and foreign-made arms to coalition-sponsored forces that undermine the authority of the legitimate Yemeni government also gives rise to questions about the compliance of coalition members with arms sales laws and end-user agreements, as well as the mandate for their military intervention. In addition, it raises concerns about the commitment of democratic states to preventing the proliferation of non-state armed entities in conflict-affected states and not allowing non-conventional and heavy arms to fall into the wrong hands, as well as their foreign and security policies toward Yemen more broadly.

The Yemeni Armed Forces

Prior to the coalition’s intervention, Yemenis opposing the armed rebellion formed popular resistance groups backing the remaining units of the military outside Sanaa. These included tribesmen, prominent leaders, soldiers, officers, and civilians who took up arms to defend their homes, regions, government, and way of life. In the first months of the military intervention, senior commanders led the rebuilding of the Yemeni Armed Forces, integrating popular resistance forces into the army using the means at their disposal. But the stockpiling of large caches of heavy and technologically advanced weapons in the highlands, most notably Sanaa and its vicinity, under Saleh, coupled with the Hadi government’s limited revenues and financial challenges, as well as the coalition’s unjustified restrictions, meant the weapons at the armed forces’ disposal were inadequate, both qualitatively and quantitatively.

Additionally, a U.N. Panel of Experts report in 2020 concluded that “coalition support to regular forces of the Government of Yemen has been inadequate, leading to an incapacity of the Government to conduct significant military operations.” While the U.N. assessment is broadly true, the counteroffensive of government forces from Shabwa to the outskirts of Aden, foiling the STC’s attempt to extend its control beyond Abyan to the east in late August 2019, demonstrated resilience, drive, and military expertise. With significant support from tribal reinforcements, they also repelled intensive Houthi attacks against Marib throughout 2020. As such, it is clear that government forces have not been totally incapacitated.

In recent months, the Yemeni Armed Forces reportedly started using reconnaissance drones, a sign of delayed adaptation to the constantly evolving Houthi war machine and strategic changes on the battlefield. Unlike Iran, which has contributed to the Houthi acquisition of equipment essential to modify and locally assemble drones and missiles, according to several UNSC reports, Saudi Arabia and the UAE have restricted the government’s ability to acquire heavy and non-conventional arms through external arms markets, undermining its legitimate right to do so. Additionally, the coalition, mainly led by the UAE in the operational theater before its drawdown announcement in mid-2019, also restricted and denied the Yemeni army access to and use of the coalition’s heavy arms, in contrast to the armaments it provided for UAE proxies and partners. This had the effect of undermining the government and constraining its tactical planning. The coalition’s control of Yemeni ports, from Aden to Nashtun in al-Mahra, also weakened the government’s ability to import arms critical for ensuring its survival, let alone those that would give it a qualitative military edge to help extend its influence and control.


The current outlook is alarming. Conventional and non-conventional arms continue to proliferate in an unregulated fashion outside of the command-and-control structures of the legitimate government, fueled by outside regional actors — Iran and the UAE — with other objectives in mind, including heightening regional instability. Moving forward, there are several recommendations that would help reduce the spread and control the flow of arms to non-state actors in Yemen.

First, the U.S. should put significant and credible pressure on both Iran and its Gulf partners to stop sending arms to actors other than the internationally recognized Government of Yemen. Second, the permanent members of the UNSC, alongside the sponsor of the Riyadh Agreement, Saudi Arabia, should support the reintegration of all militias and military formations under the authority of the government to pave the way for nationwide security reform should a comprehensive peace agreement be reached in the next two years.

Third, the United Nations Verification and Inspection Mechanism for Yemen (UNVIM) should also strengthen monitoring, surveillance, prevention, and enforcement measures to counter the ongoing flow of arms, including by the coalition — so long as it’s not liaised with and meant for the Government of Yemen forces. In June, Dryad Global predicted an uptick in arms shipments for the UAE-backed STC, after it assumed a degree of control on the island of Socotra with tacit Saudi approval. These activities should also be monitored and regulated, especially now that the STC shares power under the newly formed Riyadh Agreement unity government.

Fourth, the U.S. Treasury Department as well as the UNSC must leverage targeted sanctions, including on complicit firms, non-state recipients, individuals, brokers, and states, to reduce supply and/or diversion of arms to militant groups. U.S. political will, evident in the sanctions imposed on UAE-based firms implicated in “smuggling lethal aid from Iran to Yemen on behalf of the Islamic Revolutionary Guards Corps-Qods Force,” for instance, should continue under the Biden administration to this end.

Fifth, the U.S. should invest in building up the capacity of the Yemeni army’s counterterrorism, anti-piracy, anti-narcotic, counterinsurgency, and stabilization units, including by means of armament, logistical support, and training, to enhance the operational, tactical, and strategic abilities of government forces. The primacy of security reform, reintegration, and disarmament of militias in forthcoming transitional peace processes should make this endeavor a wartime priority. Finally, the U.S., the U.K., the EU, and permanent members of the UNSC must consider the inclusion of provisions to prevent and hold Iran accountable for its illicit transfer of conventional and non-conventional weapons beyond its borders, including drones, missiles, and relevant equipment, and/or spare parts, should the Joint Comprehensive Plan of Action be renegotiated by the Biden administration.


Ibrahim Jalal is an independent Yemen and Gulf analyst, a non-resident scholar at MEI, and a co-founder of the Security Distillery Think Tank. Mustafa Naji is a former Yemeni diplomat and a researcher in the field of social studies. The views expressed in this piece are their own.

Photo by ABDULLAH AL-QADRY/AFP via Getty Images