A radical U.S.-born cleric wanted by Yemen and the United States has been killed in an apparent American air strike in Yemen.

Yemen's defense ministry says Anwar al-Awlaki, who is linked to al-Qaida forces in the country, was killed along with several other suspected militants. A timeline was not released as to the sequence of the attack.

The Yemeni government did not offer details of the death, which was confirmed by unnamed U.S. officials.

But tribal sources and security sources within Yemen say Awlaki was killed early Friday in an air raid targeting an al-Qaida convoy in the country's east.

Reports say U.S. aircraft was used in the mission. The U.S. has previously conducted unmanned drone attacks against al-Qaida targets in the country.

Awlaki was wanted by both the U.S. and Yemen for his suspected role in terrorist attacks, including the attempted bombing of a U.S. airliner in 2009. He is also believed to have acted as an advisor to the suspect in a deadly shooting spree at a U.S. military base in Texas and the killing of a Frenchman in Yemen last year.

U.S. authorities had linked the cleric to the Yemen-based al-Qaida in the Arabian Peninsula.

The attack comes with Yemen in the throes of political crisis.

Despite months of protests demanding he leave office, Yemeni President Ali Abdullah Saleh continues to say he will not step down as long as his key political rivals retain power and influence in the country.

In an interview with The Washington Post and Time magazine this week, Mr. Saleh said a political transition plan crafted by Yemen's Gulf neighbors made it clear that “all elements” contributing to the country's civil unrest should be removed.

The president warned it would be “very dangerous” if his rivals — General Ali Mohsen al-Ahmar, who defected to the opposition, and Hamid al-Ahmar, a telecom tycoon and politician whose brother heads Yemen's most powerful tribal confederation– were to retain their positions after he resigns. He says that outcome could “lead to civil war.”

Fighting has escalated during the past two weeks. On Wednesday, anti-government tribesmen shot down a government warplane near the capital.

Yemen's foreign minister has blamed the turmoil on the opposition's refusal to accept 2006 presidential results. Abu Bakr al-Qirbi said Tuesday that Mr. Saleh is committed to pushing forward a long-stalled plan to transfer power to a deputy.

Mr. Saleh has agreed to the proposal three times since April, but has backed out each time before it could be signed.