The brother-in-law of a regional Yemeni al Qaeda leader confirmed to NBC News that the al Qaeda leader was killed overnight in a U.S. airstrike, one of a wave of strikes in Yemen that began Thursday.

Osama Haidar was in a car in Abyan province with several other men when their car was struck by either a drone or a plane, said his brother-in-law , Aly Mohamed Somly, via phone from the Yemeni capital of Sanaa. "I found out today that he and four others were hit ... and killed," said Somly.

"The car belonged to al Qaeda," said Somly. He named one of the other dead men as Radwan al Naqib. 

Yemeni media described Haidar as the leader of al Qaeda in the Arabian Peninsula (AQAP) in a portion of the governorate of Aden.

Somly said that his brother-in-law joined al Qaeda's Yemeni affiliate,after he was jailed and tortured. "Al Qaeda helped him out in jail and received him when he was released."

Somly said Haidar fought with al Qaeda against the Iranian-backed Shia Houthi rebels. He then found himself fighting Saudi and United Arab Emirates forces when those countries began fighting al Qaeda.

Emirates troops took part in the January U.S. SEAL raid on an alleged al Qaeda encampment in the mountains of Yemen that left one SEAL dead.

During the past two days, the U.S. has launched dozens of airstrikes in Yemen.