KABUL: Al-Qaeda said the suicide bombing at a US base in Afghanistan that killed seven CIA agents was "revenge" for the deaths of militants in US drone strikes in Pakistan, the US monitoring group SITE said on Thursday.

A Jordanian identified as Humam Khalil Abu-Mulal al-Balawi who was said to be a triple agent blew himself up at the base in Khost on December 30 in the deadliest attack against the CIA since 1983.

The head of Al-Qaeda in Afghanistan, Mustafa Abu al-Yazid, said the bomber wrote in his will that the attack was revenge for "our righteous martyrs" and named a number of top militants killed in US drone attacks, SITE said.

These included Baitullah Mehsud, the leader of Pakistan's Taliban blamed for a wave of deadly attacks including the killing of former Pakistan prime minister Benazir Bhutto in December 2007.

Mehsud was killed when a US missile slammed into his father-in-law's house in August last year.

Another militant named was Abu Saleh al-Somali, described as part of Al-Qaeda's core leadership and responsible for plotting attacks in Europe and the United States, who was killed in a drone strike in the North Waziristan area in December last year.

The Al-Qaeda statement surfaced after another round of US drone strikes left 11 militants dead near Pakistan's Afghan border on Wednesday. Related article: US missiles strike Pakistan

The attack also killed two contractors with XE, the controversial private security firm once known as Blackwater, US media reported.

The two apprently were among seven CIA operative and a Jordanian intelligence officer killed in the December 30 attack, reportedly by a Jordanian double agent who blew himself up inside Forward Operating Base Chapman. Related article: Blackwater staff among CIA-base victims: reports

Their deaths were reported by local newspapers in Washington state and Virginia.

The News Tribune, from the Pacific state of Washington, said 46-year-old local man Dane Clak Paresi, a Xe contractor and retired soldier, was killed in the blast.

His wife, MindyLou Paresi, told the paper she was informed her husband was nearest to the bomber when he detonated his device.

"All of the agents are national heroes because they were there to do a job, a very large job. What it was I do not know exactly, but they were heroes fighting the war against terror," she said.

The Virginia-Pilot, a newspaper near Xe's base in North Carolina, said Jeremy Wise, also a contractor and a former Navy SEAL, was killed as well.

The reports point to a continued close relationship between the CIA and Blackwater.

The firm is believed to have participated in programs to kill top Al-Qaeda terrorists in 2004, and CIA "snatch and grab" missions to capture or kill insurgents in Iraq and Afghanistan.

But the CIA had appeared to distance itself from the firm in recent years, particularly after five Blackwater employees were charged with killing 14 unarmed Iraqi civilians and wounding 18 others during an unprovoked attack at a busy Baghdad roundabout using guns and grenades in 2007.

A US judge recently dismissed criminal charges against five, but not before the firm lost its contract to provide security for US embassy diplomats in Baghdad and was reportedly stripped of other CIA contracts.

Erik Prince, the former US Navy Seal who founded Blackwater, told Vanity Fair magazine earlier this month he felt betrayed that his role in working with the CIA had become public.

"I put myself and my company at the CIA's disposal for some very risky missions," said Prince, who eschewed a role in his family's billion-dollar auto-parts firm to join the military.

"But when it became politically expedient to do so, someone threw me under the bus."

Prince's role in the CIA program was widely reported after Panetta briefed US lawmakers on its existence.