Long sought-after US-born Al-Qaeda cleric, Anwar al-Awlaqi, who was killed in a US air strike last week, used to move freely around Yemen's lawless provinces and even preach in mosques, witnesses said.

During the past few months, the radical cleric had moved between the Al-Qaeda hotbed regions of Abyan and Shabwa in the south and Marib in the east, one tribal chief told AFP on condition of anonymity.

It was in Marib that the man described by US President Barack Obama as the external operations leader of Al-Qaeda in the Arabian Peninsula, or AQAP, was killed in an air strike early on Friday.

Also killed in the raid was Pakistani-American Samir Khan, who was the editor of Al-Qaeda's English-language online magazine "Inspire".

Five other Yemenis and a Saudi were killed in the attack. Although the identity of the Saudi was not revealed, tribal sources said he was not Al-Qaeda's master bomb-maker Ibrahim Hassan al-Asiri, as earlier thought.

Awlaqi and AQAP number two, Saeed al-Shehri, escaped death on September 20, when US drones carried out several air strikes on the village of Al-Mahfad in Abyan, the tribal chief said.

The imam fled to Al-Jawf, a desert area further in the north, near the borders with Saudi Arabia, he added.

Four Al-Qaeda militants were killed in that raid, a tribal source close to the jihadist network said.

Awlaqi used to "spend most of his time in Khor al-Awaleq," a mountainous region in Shabwa province controlled by the cleric's tribe, the tribal chief said. "He also went to the nearby towns of Azzan and Rawda."

"I had attended three sermons by Awlaqi in mosques, two in Azzan and another one in Al-Rawda, during and after Ramadan," the Muslim holy month of fasting that fell in August this year, said one Shabwa resident.

"Awlaqi used to call for jihad (holy war) and for fighting Americans," he said, adding the cleric's thoughts "impressed many youths."

Another witness said he saw Awlaqi perform dawn prayers at a mosque in Loder, another Al-Qaeda stronghold in Abyan.

But the imam quickly fled after US drones were spotted flying overhead, the witness added.

Awlaqi was surrounded by tight security, according to another tribal chief, who told AFP he had met with the cleric in August upon the latter's request.

The chief said said that partisans of the radical imam asked him to meet them in a certain area from which he was taken to "an arid mountainous region."

"I saw dozens of armed men deployed on the hills surrounding the meeting area," he said.

The tribal chief said he refused Awlaqi's request to allow Al-Qaeda militants to freely pass through the area held by his tribe, which had mostly opposed the militant group.

AQAP has taken advantage of the weakening of central authority by nearly nine months of deadly protests against veteran President Ali Abdullah Saleh to bolster its presence in several southern provinces as well as Marib.

Hundreds of militants from the Al-Qaeda linked Partisans of Sharia (Islamic law) group overran Zinjibar, Abyan's capital, in May and the city and adjacent towns have since been the scene of bitter fighting with the army.

Early this year, a Yemeni court specialising in terrorism cases handed down a 10-year jail sentence in absentia to Awlaqi for taking part in an armed group and for incitement to kill foreigners.

However, the cleric's whereabouts had remained unknown and he escaped a US drone strike in early May, days after US special forces carried out a raid in which they killed Al-Qaeda chief Osama bin Laden in his hideout inside Pakistan.

Awlaqi was born in New Mexico. A charismatic preacher and fluent in English, he had a unique ability to recruit Al-Qaeda operatives in the West.

US intelligence officials believe he 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.