A British-based Islamic news agency released video footage of Saudi-born dissident Osama bin Laden today which it said was filmed just two months ago.
But the independent Arab satellite news network al-Jazeera said it had seen the tape three or four months ago and believed it was recorded in October.
The 100-second clip showed bin Laden seated outside a stone building in a camouflage smock as he spoke to unseen supporters, extolling the merits of martyrdom.
If the film were just two months old it would be the first proof that bin Laden survived the US onslaught on his militant al-Qaeda network and Afghanistan's former Taliban rulers after the September 11 suicide attacks in the United States.
Neither bin Laden's comments nor the setting of the film - under a tree against a backdrop of hills - appeared to shed light on when it was filmed.
The Ansaar news agency said Pakistani intelligence officers who supplied the video said it was shot in March.
"We can't verify or confirm it," said Ansaar journalist Mr Imran Khan. But bin Laden looks gaunt, thinner and paler. He said he believed it was filmed in the southern Afghan border town of Spin Boldak.
He said the footage was part of a 40-minute film which the agency obtained in Pakistan four weeks ago. It was brought to Britain on an encrypted CD-ROM which was only decoded and transcribed last week, Khan said.
"Concerning the situation that we are in, we must praise Allah that he has allowed us to follow the path of (men who are among) the best of creation," bin Laden said.
"We ask Allah for victory, and we ask Allah to grant us martyrdom," added Washington's chief suspect for the September 11th suicide plane attacks in the United States.