"A senior al-Qaeda leader in Afghanistan, Abu Laith al-Libi, has been killed, Western counter-terrorism officials have told the BBC.
News of his death emerged on a website used by Islamist groups. Ekhlaas.org said he had 'fallen as a martyr'.
There is speculation that he was killed by a US missile strike in the North Waziristan area of Pakistan this week.
A dozen militants were reported killed in the attack. US intelligence agencies said they were checking the reports.
A Pakistani daily paper, the News, reported that the suspected US strike was aimed at Libi and another senior figure, Obaidah al-Masri.
Libi has appeared in a number of al-Qaeda videos. In November he appeared alongside al-Qaeda second-in-command Ayman al-Zawahri.
He has acted as a spokesman for the group, announcing in 2002 that Osama Bin Laden and Taleban leader Mullah Omar had survived the US invasion of Afghanistan.
Libi was under US intelligence surveillance and most details about him are classified, says the BBC's security correspondent Frank Gardner."
ABU LAITH AL-LIBI
Born: Libya, around 1941
Description: 6'4' tall, solid build, dark hair and eyes, scars on back
Role: Senior operations commander; al-Qaeda spokesman