Video purportedly of a Jordanian who blew up CIA agents in Afghanistan has shown him vowing revenge for Pakistani Taliban chief Baitullah Mehsud's death.

In a clip broadcast on al-Jazeera TV, a man said to be bomber Humam Khalil Abu-Mulal al-Balawi says Mehsud must be avenged "inside and outside America".

The footage appears to show him next to Mehsud's successor, Hakimullah Mehsud, although he is not named in the video.

The clip's authenticity is unconfirmed. Eight people died in the bomb attack.

Seven were US CIA agents and one was a Jordanian intelligence officer.

The attack at Forward Operating Base Chapman in Afghanistan's Khost province was the deadliest against US intelligence officials since the US embassy in Beirut was bombed in 1983.

Humam al-Balawi is said to have been a Jordanian doctor turned double agent, having originally been recruited by the Jordanians to spy on al-Qaeda.

His father, Khalil Balawi, said the man who appeared on the video was definitely his son.

Speaking in Jordan, he blamed "American oppression against the Muslim world" for his son's act.

In the video clip shown on al-Jazeera, the man purported to be al-Balawi says he is sending a message to the "enemies of Islam", who he names as Jordan's intelligence services and the CIA.

"We say that we will never forget the blood of our leader, Baitullah Mehsud," he says.

"What remains is to avenge him inside and outside America."

The man in the clip, speaking in Arabic, says the Pakistani Taliban leader paid with his life for offering to shelter al-Qaeda leader Osama bin Laden.

The man appears to dismiss the idea he himself was in the service of the Jordanians or US, saying that a Muslim jihadist "will not sell his religion".

The IntelCenter, a US-based group monitoring extremist sites, said the video had been released by the Pakistani branch of the Taliban.

The bombing of the American base was an audacious attack which sent shockwaves through western intelligence services, the BBC's Orla Guerin in Islamabad reports.

So far there has been no comment from the authorities in Pakistan, she says, but the video is bound to increase pressure on them to crush militant groups on their soil who attack western forces across the border in Afghanistan.

Baitullah Mehsud was killed in a US missile attack in the tribal region of South Waziristan, which borders Afghanistan, in August last year.

Two months later, the Pakistani military launched a major offensive in the region.

More than 600 people have died in militant attacks in Pakistan since then, most of them believed to be in reprisal for the army's campaign against the Taliban.

Correspondents say Hakimullah Mehsud is thought to be in South Waziristan.

Forward Operating Base Chapman, a former Soviet military base in Afghanistan, is used not only by the CIA but also by provincial reconstruction teams, which include both soldiers and civilians. The airfield is reportedly used for US drone attacks on suspected militants in neighbouring Pakistan.