US drone strikes

The first incident was reported on May 11, 2015, when a U.S drone strike killed four AQAP militants traveling in a car around the Mukalla, including the commander Mamoun Abdulhamid Hatem.^[16] AQAP confirmed Hatem's death in September 2018.^[17]

On June 10, 2015, suspected drone strikes attacked and killed three AQAP fighters, including a commander, at the Mukalla port.^[18] Six days later, on June 16, AQAP confirmed that a U.S drone strike had killed its AQAP Emir, Nasir al-Wuhayshi, and that it had replaced him with the group's military chief, Qasim al-Raymi.^[19][20] A day after Nasir's death, AQAP executed two Saudi citizens in its territory after accusing them of being spies of U.S and helping them to find the location of the AQAP leaders.^[21]

On June 25, a U.S drone strike killed four AQAP militants - including a commander - inside their car outside an AQAP training facility in Mukalla. Another strike hit nearby, but no casualties were reported.^[22]

On July 3, four AQAP fighters were killed by a U.S drone strike inside an army base.^[23]

On July 10, U.S drone strikes killed 10 AQAP fighters inside a vehicle also carrying a container loaded with weapons, including three senior leaders among the dead.^[24]

On August 12, a U.S drone strike killed five AQAP members inside a car, when they traveling to Mukalla.^[25]

On September 9, 2015, suspected U.S drone strikes targeted a group of AQAP militants in the Riyan Airport near Mukalla. Reports said that two to four militants were killed, along with four civilians.^[26] Some days later, on September 12, five AQAP fighters were killed in another U.S drone strike inside Mukalla.

On March 23, 2016, a U.S airstrike killed more than 50 AQAP fighters in a camp in Mukalla at dinner time, and injured more than 30.^[27]

UAE-led ground offensive

On April 24, 2016, UAE soldiers entered Mukalla, successfully killing around 30 AQAP fighters. On the same day, Al-Qaeda fighters began withdrawing from the city to other parts of Hadramaut Province. This occurred after negotiations with local tribesmen and clerics, allegedly to avoid injury to civilians and destruction of the city from attacks against AQAP fighters.^[28] By April 25, Pro-Hadi Government forces and UAE forces had fully recaptured Mukalla, along with the rest of the coastal regions of the Hadramaut Province.^[13] On the same day, coalition officials stated that more than 800 AQAP fighters had been killed in the fighting, but that number was disputed by Yemeni journalists who covered the event, who said that the group retreated after negotiations. By 26 April, Mukalla and the rest of the surrounding towns and cities had been cleared of AQAP forces.^{[13][29][30][31]}

US Defense Secretary James Mattis called the UAE-led operation a model for American troops, citing how the United Arab Emirates Armed Forces liberated the port of Mukalla from AQAP forces in 36 hours after being held by AQAP for more than a year.^[32]

US support

On 6 May, Navy Captain Jeff Davis, a Pentagon spokesman, confirmed that US forces were deployed near the city of Mukalla during the battle, and but did not disclose the number of troops.^[33]