Tribe members stood atop a military vehicle they took from an army base in Shihr, a city in Yemen's eastern Hadramawt province, April 4, 2015. Reuters

Al Qaeda militants in Yemen captured a major airport and an oil terminal Thursday in the country’s south, officials told the Associated Press. The militant group has taken control of various territories in Yemen amid weeks of fighting between government forces loyal to exiled Yemeni President Abed Rabbo Mansour Hadi and Iran-backed Shiite rebels known as Houthis.

Al Qaeda reportedly seized the Riyan airport in Mukalla from one of Yemen's infantry units. A local activist said the soldiers offered little resistance before they withdrew from the airport, the AP reported.

The attack came weeks after al Qaeda fighters took control of Mukalla from forces loyal to former Yemeni President Ali Abdullah Saleh. Militants freed 300 prisoners, including one of al Qaeda’s Saudi-born leaders, from Mukalla’s main prison, looted government buildings and blocked the city’s access points.

“People are terrified,” a Mukalla activist told the AP on April 2. “They never expected that the city falls so easy in the hands of al Qaeda.”

Al Qaeda has formed alliances in Sunni tribes to combat the Houthis, the Shiite faction that seeks to oust Hadi’s government. Hadi was forced to flee Yemen earlier this year to escape the Houthis. A U.S. drone strike in Yemen on Tuesday killed one of the leaders of al Qaeda in the Arabian Peninsula, the New York Times reported.

A Saudi-backed coalition has carried out military operations, including airstrikes, against the Shiite rebels, while Yemen’s government has accused Iran of providing support to the Houthis. “The Houthi rebels are puppets of the Iranian government, and the government of Iran does not care for the fate of ordinary Yemenis; it only cares about achieving regional hegemony. On behalf of all Yemenis, I call on the agents of chaos to surrender and to stop serving the ambitions of others,” Hadi wrote in an April 12 New York Times op-ed.

More than 600 people, including civilians, have died as a result of fighting and airstrikes in Yemen, while more than 2,000 have been wounded, the World Health Organization estimates, as CNN reported.