Conflict in Yemen is more complex than a Sunni–Shia conflict, or proxy war between Iran and Saudi Arabia. While armed groups in Yemen are often put in a 'pro-government' or 'pro-Houthi' camp, most Yemenis do not support either. Rather, myriad small groups are often organised along tribal lines, and have their own identity, ideology, and goals.?
Pro-government forces, supported militarily and politically by a Saudi-led coalition, are led by President Hadi and his cabinet. However, the Yemeni army is deeply divided, with units loyal to President Hadi fighting pro-Houthi units.? Pro-government forces aim to regain control of Houthi-controlled areas, and also started to carry out operations against Al Qaeda.? President Hadi has limited support among the wider population.?The Yemeni army factions that support 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 often dubbed as loyal to the Hadi government, they are mostly alligned 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 former President Saleh, who was once the rival they rose against.? 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 having shared power via a ten-member 'supreme political council' since late July.? 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 considered to be 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 President Hadi and the Saudi led coalition. The statement of Saleh was followed by heavy fighting between Houthi and Saleh forces, and Saleh was killed by Houthis on 4 December in the capital Sana'a.? The number of Houthi fighters is around 30,000.? Iran is allegedly supporting Houthi forces with weapons and financial resources; 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. ?
The Southern Resistance movement, or Al Hirak, is a coalition of allied militias, based in the governorates that constituted South Yemen before unification.? The Southern Resistance were used by the Hadi government 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.?Following the dismissal of Southern Movement politicians from the Hadi government in April 2017, the Movement has created the 'Transitional Political Council of the South'; effectively creating a third government.?
Al Qaeda in the Arabian Peninsula (AQAP): AQAP is based in the south and east of the country, and also joins the fight against al Houthis.?AQAP has expanded its support base within the local Sunni population by fighting the al Houthis alongside local tribal forces in al Bayda in central Yemen. ?Initially AQAP capitalised on the security vacuums that came into existence after fighting between pro-government and Houthi forces. Since April 2016, however, the Hadi government and Saudi-led coalition have increased operations against AQAP, seeking to diminish their physical presence especially in al Mukalla, which is one of AQAP's stronghold areas, but despite this AQAP has continued attacks particularly in Abyan, Aden, and Hadramawt governorates. ?
Islamic State (IS) 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 and situation remained calm until November 2017 when ISIS fighters resumed suicide attacks in Aden.? On 24 February 2018, ISIS claimed responsibility for an attack on the headquarters of a Yemeni counter-terrorism 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, Bahran, Jordan, Senegal, Morocco, Sudan, and Egypt are members of the coalition.? Qatar was a member of the coalition until being expelled in June 2017 following the diplomatic crisis.? An estimated 10,000 ground troops have been deployed by the coalition. Troops were initially sent by the UAE, but 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, UK and France, have been supplying weapons, including 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.?