In this image taken from undated video made available from Taliban sources Saturday purportedly showing Humam Khalil Abu Mulal al-Balawi, right, reading a statement to camera vowing revenge for the death of Pakistani Taliban chief Baitullah Mehsud, while sitting next to the new leader of the Pakistani Taliban, Hakimullah Mehsud.

Kabul ? In a video broadcast after his death, the Jordanian suicide bomber who killed seven CIA employees sits cross-legged on the floor next to the new chief of the Pakistani Taliban, confirming the group was behind the brazen attack in eastern Afghanistan.

Yet multiple insurgent groups have claimed responsibility for the bombing, and a senior Pakistani militant told The Associated Press that al-Qaida and Afghan Taliban fighters were also involved in one of the worst attacks in the U.S. intelligence agency’s history.

The suicide attack inside the CIA base — which the bomber said was meant to avenge the death of the former Pakistani Taliban leader in a CIA missile strike — could prompt the U.S. to further pressure the government of Pakistan to crack down on militants who operate on both sides of the Afghan-Pakistani border. U.S. missile strikes against targets on the Pakistan side already are on the rise.

Seven CIA employees and a Jordanian intelligence officer were killed Dec. 30 when the suicide bomber detonated his cache of explosives at Camp Chapman, a tightly secured CIA base in Khost province, a dangerous region southeast of the Afghan capital Kabul.

The CIA had cultivated the bomber — a Jordanian doctor identified as Humam Khalil Abu-Mulal al-Balawi — in hopes of obtaining information about al-Qaida’s second in command, Ayman al-Zawahri.

Defending his agents, CIA Director Leon Panetta said the bomber was about to be searched before the blast occurred.

“This was not a question of trusting a potential intelligence asset, even one who had provided information that we could verify independently. It is never that simple, and no one ignored the hazards,” Panetta wrote in a Washington Post op-ed piece posted online Saturday. “The individual was about to be searched by our security officers — a distance away from other intelligence personnel — when he set off his explosives.”

Al-Balawi turned out to be a double-agent — perhaps even a triple-agent. In the 1 1/2 minute video, the bomber said he attacked the CIA to avenge the death of Baitullah Mehsud, the longtime leader of the Pakistani Taliban who was killed in August.

“This jihadi attack will be the first revenge operation against the Americans and their drone teams outside the Pakistan border,” the bomber said on the video. Al-Balawi — wearing an Afghan hat and camouflaged jacket — said the Pakistani Taliban, now under the leadership of its new chief Hakimullah Mehsud, would fight till victory.

“We will never forget the blood of our emir Baitullah Mehsud,” said al-Balawi. “We will always demand revenge for him inside America and outside.”

Statements by Afghan Taliban and al-Qaida leaders since the attack have confused efforts to figure out which group’s fingerprints were on the blast that struck a blow to the CIA’s field expertise in Afghanistan.

A senior militant with the Pakistani Taliban told AP the suicide bomber received training from Qari Hussain, a leading commander of the Pakistani Taliban believed to have run suicide bombing camps. The militant, who spoke on condition of anonymity because of security reasons, said al-Qaida and the Haqqani network, a highly independent Afghan Taliban faction, also were involved.

Hussain’s Lashkar-e-Janghvi group, a violent anti-Shiite Muslim organization, is believed to provide a reservoir of suicide bombers and has been linked to some of the more spectacular bombings in Pakistan and the death of former Pakistani Prime Minister Benazir Bhutto.

Arsala Rahmani — a former minister in the Taliban government that was toppled in the U.S.-led invasion of Afghanistan following the Sept. 11 terrorist attacks — said the Pakistani and Afghan Taliban and al-Qaida often work in unison against Western forces.

“Most of the time, the Afghan Taliban, Pakistani Taliban and al-Qaida … they are fighting together,” said Rahmani.

A senior NATO intelligence official, who spoke on condition of anonymity because he wasn’t authorized to release the information, said all insurgent groups have subordinated themselves to the senior Afghan Taliban leadership, believed to be based in Quetta, Pakistan.