The United States says it is withdrawing its troops from al-Anad air base in Yemen because of increased security there, Yemeni sources said.
About 100 troops, including special forces commanders, are leaving the base near the southern city of Al-Huta, officials said.
On March 20, al-Qaeda fighters stormed al-Houta, although they were later expelled by the Yemeni army.
The U.S. military has not confirmed the evacuation.
It comes the day after suicide bombers killed at least 137 people in the capital, Sanaa. The militants, who have joined forces with the Islamic State, said they had carried out the attack.
Tensions are rising in Yemen between various powerful armed elements, including Hussein, al-Qaeda and ISIS rebels.
US troops at al-Anad air base are preparing Yemeni fighters for attacks on al-Qaeda operatives.
On March 20, al-Qaeda fighters took control of al-Hutu, near the air base. But later the militants were repulsed by the army.
The United States closed its embassy in Sana’a in February after the city was captured by rebel forces Hussein.
Yemen is the base of al-Qaeda in the Arabian Peninsula (AQAP), a powerful branch of a group of jihadist militants.
ISIS is also gaining ground in Yemen after establishing a base in the country in November.