ADEN, Yemen — At least two suspected Islamist militants were killed in a drone missile strike in Yemen's southern Shabwa province, the latest in a surge since Washington warned of possible attacks by al-Qaida in the region.

At least 37 people have been killed in just over two weeks in a campaign targeting insurgents linked to Al-Qaida in the Arabian Peninsula (AQAP), described by U.S. officials as the most dangerous branch of the global jihadi network.

That campaign has been stepped up after intercepted communication between AQAP leader, Nasser al Wuhayshi and Ayman al-Zawahiri, head of al-Qaida, along with other intelligence prompted Washington to close 19 U.S. embassies this month.

"The car was completely obliterated and the two men inside it were killed," a local official said, adding the strike happened late on Monday. He gave no further details.

Yemen is one of a handful of countries where Washington acknowledges using drones, although it does not comment publicly on the practice.

Security in Yemen is of regional and global importance.

AQAP has previously plotted unsuccessfully to attack international airliners and is seen in Washington as a potential threat to Yemen's neighbor Saudi Arabia, the world's top oil exporter, and Red Sea oil tankers.

On Monday, AQAP leader Wuhayshi said he would free jailed Islamist militants soon.