Yemeni security officials say hundreds of troops loyal to the internationally recognized president have launched an operation to drive Al Qaeda and Islamic State fighters out of southern coastal areas the extremists have seized amid the country's complex civil war.

The officials say troops loyal to President Abed Rabbo Mansour Hadi are receiving air support from the Saudi-led and U.S.-backed coalition, which until now has mainly targeted Shiite Houthi rebels.

They say the aircraft struck targets in Mukalla, an Al Qaeda stronghold and the capital of Hadramawt province. The officials spoke on condition of anonymity because they were not authorized to brief journalists.

Al Qaeda's affiliate in Yemen, viewed by Washington as the group's most dangerous offshoot, has exploited the conflict between the rebels and government forces to expand its footprint.