Gunmen have killed at least 32 soldiers in attacks on two army posts in southern Yemen on Monday, a day after a wanted leading fighter died in an air raid, a military official said.
Suspected al-Qaeda fighters attacked the military posts outside the city of Zinjibar, which they have controlled since May last year, said the official, speaking on condition of anonymity. Four officers were among those killed, he said.
A medic in Aden confirmed the toll, adding that 11 others were wounded.
The attacks came after Yemeni al-Qaeda leader Fahd al-Quso, who was wanted in connection with the bombing of the USS Cole in 2000, was killed in an air strike in eastern Yemen on Sunday.
The October 2000 attack on the US Navy destroyer in Yemen's port of Aden killed 17 sailors and wounded 40 more.
Quso was killed when two missiles slammed near his home in Rafadh, east of Ataq, the provincial capital of Shabwa province, a tribal chief said, adding that two of the fighter's bodyguards were also killed in the raid.
Quso's name figured on an FBI list of most wanted terrorists, along with a reward of up to $5m for information leading to his arrest.
Another military official said the army was anticipating an al-Qaeda retaliation for the killing of Quso, saying that an alert was sent out to all units to expect an attack by the "enemy" following Sunday's air raid.
Last September, Anwar al-Awlaki, a Yemeni-US citizen, was killed in a drone attack that Barack Obama, the US president, described as a "significant milestone".
Awlaki had been linked to al-Qaeda in the Arabian Peninsula (AQAP) and for plotting abortive attacks on US targets.
The use of drones has been controversial in Yemen, Afghanistan and Pakistan, where the US is fighting al-Qaeda-linked groups.
Washington has never formally acknowledged the use of drones against al-Qaeda in Yemen, and the Yemeni government continues to deny that such air strikes take place.
The US wants Yemen's new president, who took office after a year of mass protests against his predecessor that split the military into warring factions, to unify the army and rein in al-Qaeda operatives.
A group linked to al-Qaeda seized chunks of territory in south Yemen during the uprising against former President Ali Abdullah Saleh, a staunch US ally, and killed about 100 Yemeni troops in a single attack near one of those areas in March.