Yemeni military officials say suspected al-Qaida militants have killed at least 20 soldiers during a surprise attack in the country's south.

The officials, who spoke on the condition of anonymity, said Monday's assault occurred in the volatile Abyan province.

The attack comes a day after a senior al-Qaida leader in the Gulf region was killed by a U.S. airstrike in Yemen. Officials say Fahd al-Quso was hit by a missile in Rafth, in the country's southern Shabwa province, along with another al-Qaida operative.

The Yemeni embassy in Washington said Quso was “one of Yemen's most wanted terrorists.” The terror group Al-Qaida in the Arabian Peninsula has confirmed his death.

The Federal Bureau of Investigation in Washington had placed Quso on its “most wanted” list. He was charged in a U.S. court with involvement in the October 12, 2000 bombing of the USS Cole at a port in Yemen – an attack that killed 17 American sailors and wounded dozens of others.