DOWAAN, Yemen — Al Qaeda’s branch in Yemen took control of a major airport and an oil export terminal in the southern part of the country on Thursday, expanding the resurgent militant group’s reach just two weeks after it seized the nearby city of Al Mukalla and emptied its bank and prison.

Local officials said that fighters belonging to the group Al Qaeda in the Arabian Peninsula, also known as AQAP, took control of the Riyan Airport and a nearby military base outside Al Mukalla, the fifth-largest city in Yemen. The group also seized the Dhabah oil terminal on the Arabian Sea coast, which the group had tried to capture before, according to Yemeni officials.

Al Qaeda is capitalizing on the expanding multisided war in Yemen and the collapse of its government to carve out territory for itself. When its fighters stormed Al Mukalla, the capital of Hadhramaut Province, they seized government buildings, looted the central bank office and freed hundreds of inmates from the city penitentiary, including a senior leader of the group.

Al Qaeda’s adversaries in Yemen are largely in disarray or distracted by other fighting. Military units have melted away or put up little resistance as Al Qaeda has advanced. The Houthis, a militia movement from northern Yemen that is considered Al Qaeda’s most determined foe, have been preoccupied with battles against rival militias across the country, and their fighters have been battered by aerial assaults from the Saudi-led Arab coalition, which is trying to restore the exiled government to power.