Conflict in Yemen is more complex than a Sunni–Shia clash or a proxy war between Iran and Saudi Arabia. Although armed groups in Yemen are often categorised as 'pro-government' or 'pro-Houthi', most Yemenis support neither. Rather, myriad small groups are often organised along tribal lines, and have their own identity, ideology, and goals.?
Hadi and his cabinet lead pro-government forces, supported militarily and politically by a Saudi-led coalition. However, the Yemeni army is deeply divided, with units loyal to Hadi fighting pro-Houthi units.? Pro-government forces aim to regain control of Houthi-controlled areas, and have carried out operations against Al Qaeda.? Hadi has limited support among the general population.?The Yemeni army factions that back him are mostly active in northern governorates. Salafist fighters, including Al Qaeda in the Arabian Peninsula, have supported the fight against the Houthis in southern governorates.?Though many fighting groups are dubbed as loyal to the Hadi government, most are aligned through anti-Houthi sentiments.
The Houthis, also referred to as Ansar Allah, are a group of Zaydi fighters led by Abdul Malik al-Houthi, based in northern Yemen. They aligned with Saleh, once their rival.?Saleh was closely affiliated with the General People's Congress (GPC) party. The Houthis and GPC established a new government in late November 2016, after sharing power via a 10-member 'supreme political council' for four months.? Factions in the Yemeni army allied with the Houthis include members of the former Republican Guard, a unit perceived to be aligned with Saleh.?
The alliance between the Houthis and Saleh was pragmatic and ended in December 2017, after Saleh distanced himself from the Houthis' ballistic missile campaign against Saudi Arabia and expressed interest in negotiating with Hadi and the Saudi-led coalition. Heavy fighting between Houthi and Saleh forces followed and Saleh was killed by Houthis on 4 December in Sana'a.?There are about 30,000 Houthi fighters.? Iran allegedly provides weapons and financial resources to Houthi forces; this support is thought to have increased in February-March 2017 and is now crucial to the forces. ? The political leader of the Houthi Supreme Political Council, Saleh al-Samad, was killed in an airstrike on 19 April 2018. ?
The Southern Resistance movement, or Al Hirak, is a coalition of allied militias, based in the governorates that constituted South Yemen before unification.? The Hadi government used the Southern Resistance to re-establish control in Aden, after the Houthis took over in July 2015. The group continued to exercise considerable control in Aden and the southern governorates, where people feel they have been marginalised by the north.?After Southern Resistance politicians were dismissed from the Hadi government in April 2017, the movement created the 'Transitional Political Council of the South', effectively creating a third government.?
Al Qaeda in the Arabian Peninsula (AQAP): AQAP, based in the south and east of the country, fights the Houthis.?AQAP has expanded its support base within the local Sunni population by fighting the Houthis alongside local tribal forces in al Bayda in central Yemen. ?Initially, AQAP capitalised on the security vacuums that developed after fighting between pro-government and Houthi forces. Since April 2016, however, the Hadi government and the Saudi-led coalition have intensified operations against AQAP, seeking to diminish its physical presence, especially in al Mukalla, one of AQAP's strongholds. Nevertheless, AQAP has continued attacks, particularly in Abyan, Aden, and Hadramawt governorates. ?
Islamic State (ISIS) has a small branch in Yemen, estimated at 200 members, and has profited from the security vacuum.? The first claimed ISIS attack targeted a Shi'ite mosque in Sana'a in 2015.?Although it had eight active cells in 2015, only two cells (Aden and Hadramawt) claimed attacks in 2016. The situation remained calm until November 2017, when ISIS fighters resumed suicide attacks in Aden.? On 24 February 2018, ISIS claimed responsibility attacking the headquarters of a Yemeni counterterrorism unit in Aden, killing 14 people and wounding at least 40.?
Saudi-led coalition: A coalition of Arab countries began airstrikes in support of pro-Hadi forces on 26 March 2015. The UAE, Kuwait, Bahrain, Jordan, Senegal, Morocco, Sudan, and Egypt are members of the coalition.?Qatar was a member of the coalition until June 2017, when it was expelled during a diplomatic crisis.? The coalition has deployed an estimated 10,000 ground troops. The UAE initially sent troops, who are increasingly being replaced by mercenaries and Sudanese fighters.?Saudi Arabia is believed to have a strong influence over the Hadi government.?
Other international involvement: Several western countries, including the US, the UK and France, have supplied weapons, such as cluster munitions, to Saudi Arabia. These weapons have also been used in unlawful airstrikes.?These airstrikes often target vital infrastructure, including roads, farms, and markets. The US has trained Saudi pilots and refuels fighter jets from the Saudi-led coalition.? The US has also carried out drone strikes on AQAP targets in southern Yemen since 2016.?