Suspected US air strikes took out a raft of top Al-Qaeda leaders in Yemen barely two weeks after a drone killed US-born jihadist cleric Anwar al-Awlaqi, provincial and tribal sources said Saturday.

The nine killed in Friday evening's triple raid included a son and cousin of Awlaqi, as well as three other members of his tribe and the media chief of Al-Qaeda's feared Yemen arm, the sources told AFP.

The Yemeni defence ministry confirmed that seven Al-Qaeda militants, including its regional media chief, had been killed in a raid.

But it reiterated its standard denial of US involvement in offensive operations on Yemeni soil and insisted its own forces carried it out.

A member of the Awlaqi tribe said the tribal members killed included Awlaqi's 21-year-old son Abderrahman and Sarhan al-Qussa'a, brother of Fahd al-Qussa'a, a leader of Al-Qaeda in the Arabian Peninsula he said was on a US wanted list.

The defence ministry said that AQAP's Egyptian media chief Ibrahim al-Banna'a was also among the dead, describing him as wanted "internationally" for "planning attacks both inside and outside Yemen."

Banna'a was "in charge of the media arm of AQAP" and was one of the group's "most dangerous operatives," the ministry said.

The trio of strikes came in the militant-held town of Azzan in Shabwa province, one of three in Yemen's restive southeast that Al-Qaeda has turned into strongholds.

"Three strikes, apparently American, which were launched against positions held by Al-Qaeda militants in Azzan, one of the group's bastions, killed seven of them," a Shabwa provincial official said.

One of the strikes hit a mosque near the apparent primary target of the raid, the official said, speaking on condition of anonymity.

A number of suspected militants were also wounded and were taken to Azzan hospital, which is under the control of the militants, he added.

A police officer in Azzan told AFP later that two others died of wounds, bringing the death toll to nine.

In an apparent revenge attack, saboteurs launched a rocket-propelled grenade assault on a pipeline serving the key Shabwa gas terminal of Balhaf, forcing the suspension of exports, an engineer at the facility said.

The saboteurs struck in the Al-Hadhina district, just two kilometres (a little over a mile) from the Balhaf terminal on the Gulf of Aden, another Shabwa provincial official said, asking not to be identified.

"The pumping of liquefied natural gas from the Balhaf terminal was stopped," the engineer said.

"The pipeline was badly damaged, resulting in halting production," he said, adding that the pipeline was still on fire.

"We have not succeeded in containing the fire because the hole caused by the explosion is very big," he said, adding that fixing the pipeline "could take weeks."

Huge columns of flame and plumes of smoke were visible from as far as 25 kilometres (15 miles) away, witnesses told AFP.

There was no immediate claim for the attack but the provincial official said he thought it likely to have been an Al-Qaeda attack carried out in retaliation for the killing of their leaders.

"I think it is a response to the air strikes," the official said.

Yemen routinely denies that the United States carries out offensive operations on its territory, insisting that it plays a purely logistic and intelligence role in support of Yemen's own counter-terror operations.

But last month, The Washington Post reported that the United States was building an array of secret new drone bases to strike Al-Qaeda targets in Yemen and Somalia.

On Monday, Al-Qaeda in the Arabian Peninsula confirmed the death of Anwar al-Awlaqi in a US drone strike on September 30.

The group vowed to exact revenge for the loss of Awlaqi in the raid, which US President Barack Obama hailed as a "major blow" to Al-Qaeda worldwide.

US intelligence officials believe Awlaqi was linked to a US army major charged with shooting dead 13 people in Fort Hood, Texas, and to a Nigerian student accused of trying to blow up a US airliner on December 25, 2009.

He was also believed to be the leader of AQAP's overseas operations.

AQAP has taken advantage of 10 months of deadly protests against veteran President Ali Abdullah Saleh to bolster its presence not only in Shabwa, but also in adjacent Marib and Abyan provinces.

Yemen troops have been fighting hundreds of militants from the Al-Qaeda linked Partisans of Sharia (Islamic law) group in Abyan since they overran the provincial capital Zinjibar and adjacent towns in May.

Well over 300 Yemeni soldiers and tribal auxiliaries have been killed in the battle to retake Zinjibar, according to official figures.