Al-Qaida in the Arabian Peninsula, Yemen's branch of the terrorist cabal, claimed responsibility for a series of attacks on the United States last year.
Intelligence officials singled out AQAP as a top threat to the United States and U.S. President Barack Obama put its leader, Anwar al-Awlaki, in his hit list.
Two suspected al-Qaida leaders identified by Yemen's official Saba news agency as Musaed and Abdullah al-Harad were killed in a raid in southern Yemen.
U.S. military forces last year sent unmanned aerial vehicles to Yemen as part of an effort to target AQAP leaders operating in the country. A U.S. official who spoke with The Washington Post on condition of anonymity said U.S. aircraft had patrolled parts of Yemen but never before launched an attack on AQAP targets.
The official added that the Yemeni targets weren't gleaned from information seized during the weekend raid on slain al-Qaida leader Osama bin Laden's hideout in Pakistan.
Abu Bakr Abdullah al-Qirbi, Yemen's foreign minister, told CNN last year that Washington was helping in the Yemeni fight with unmanned drones.
"The (drone) attacks are undertaken by the Yemeni air force but there is intelligence information that is exchanged about the location of the terrorists by the Americans," he said.
Notable deaths of 2014 [PHOTOS]