The man believed to be al-Qaeda's commander of operations in Afghanistan, Mustafa Abu al-Yazid, has given a rare television interview.
He confirmed to the Pakistani TV station Geo that al-Qaeda carried out the June bombing of the Danish embassy in the Pakistani capital, Islamabad.
Geo say the interview was carried out in the Afghan province of Khost.
This is the first interview granted by a senior al-Qaeda member to the independent media since 2002.
It was conducted by Geo TV's reporter Najib Ahmad in an undisclosed location in Khost, in the east of the country.
Mustafa Abu al-Yazid is also known by the alias Sheikh Saeed.
The 53-year-old Egyptian, wearing a commando jacket, a white turban and dyed beard, spoke to the camera in Arabic, holding a Geo microphone in hand.
He confirmed that an al-Qaeda operative carried out the 2 June suicide attack on the Danish embassy in Islamabad.
"We are proud of that attack, and I had congratulated my colleagues for conducting it successfully," he said.
"We had chosen a time for the attack when there would be no innocent Muslims around," he added. All of the eight people who died in the attack were reported to have been Muslims.
Shortly after the attack Mustafa Abu al-Yazid said on the internet that the attack was in revenge for the reprinting by Danish newspapers of a cartoon of the Prophet Muhammad considered blasphemous by many Muslims.
Mustafa Abu al-Yazid is understood to be the operational commander of al-Qaeda in Afghanistan - a position which the Western intelligence community has long viewed as pivotal to the planning and execution of militant attacks around the world.
He is also reported to have managed the finances for the 11 September, 2001 attacks in New York and Washington.
He told the Geo interviewer that al-Qaeda was "properly involved" in those attacks, as well as the 1998 attacks on US embassies in Kenya and Tanzania.
Mustafa Abu al-Yazid also denounced the Pakistani government for fighting Islamic militants, justified suicide attacks and predicted victory for Taleban and al-Qaeda forces in Afghanistan.
He is believed to be an al-Qaeda veteran who was jailed in Egypt in 1982 in connection with the assassination of Egyptian President Anwar Sadat.
He is thought to have climbed to the number three position in al-Qaeda about a year ago when his predecessor, Abu Ubaida al-Masri, died of hepatitis in Pakistan.
This is the first interview given by a senior al-Qaeda figure since May 2002, when two key figures in the 9/11 attacks, Khalid Sheik Mohammed and Ramzi bin al-Shibh, were questioned by a reporter for the al-Jazeera television channel.