Several of Osama Bin Laden's bodyguards are among prisoners currently being held in a prison camp in Guantanamo Bay in Cuba, US reports say.

The last intelligence on Bin Laden was in Tora Bora in Afghanistan last December

The number of men being held is unknown, and it is not clear what, if any information, authorities have been able to obtain from them, although they are thought to have been in the camp for several months.

The news came as intelligence officials said that Bin Laden's son, Saad, had begun playing a prominent role in his father's al-Qaeda network since the group went into hiding following the US campaign in Afghanistan.

Sources told CNN network that if the bodyguards had been captured away from Bin Laden there is a good chance that he is dead.

Son's involvement

However others said there was not enough information to conclude that Bin Laden, leader of the al-Qaeda terror network suspected of ordering the 11 September attacks, is dead.

Osama Bin Laden's video sightings

7 October: Warns US will never be safe 3 November: Attacks UN and Arab leaders 14 December: US releases video it says shows Bin Laden "boasting" about 11 September 26 December: Bin Laden says terrorism "blessed" 15 April: Tape showing alleged 11 September hijacker spliced with clips of "recent" Bin Laden said by US to be "dated" 22 April and 19 May: Two tapes found in Afghanistan and UK in which the UK is threatened are thought to be old

"He [Bin Laden] has a very large security detail, so their presence there does not tell one anything," an official told Reuters news agency.

"And none of them, to my knowledge, have said that he's dead."

US authorities also said on Tuesday that Saad - one of Bin Laden's eldest children - has become more active in financing and other logistical support for several al-Qaeda operations.

They also suspect he was involved in the bombing of a synagogue in Tunisia earlier this year, which both the US and Germany believe to be the first al-Qaeda attack since 11 September.

But officials said it was unlikely that Saad - thought to be in his early 20s - had taken charge of the group.

Speculation

The fate of Osama Bin Laden has led to much speculation across the world, with most admitting they are unsure whether the al-Qaeda leader is alive or dead.

A series of videos either found by US forces during the war in Afghanistan or sent to global media outlets appeared to show Bin Laden growing progressively weaker and more gaunt as attacks on al-Qaeda and the Taleban regime progressed.

Most recently, Indian Defence Minister George Fernandes on Monday caused controversy by saying he had information that Bin Laden was living in Pakistan.

His comments drew furious denials from Pakistani authorities, who have consistently denied that Bin Laden is in the country.

Credible intelligence

Earlier this month the FBI's counter-terrorism chief, Dale Watson, said he thought Bin Laden was "probably" dead, despite admitting he had "no evidence".

The head of Germany's foreign intelligence unit, August Hanning, days earlier claimed he had received information that Bin Laden was hiding, along with 5,000 al-Qaeda operatives, in the border region between Afghanistan and Pakistan.

The US says the last credible intelligence they obtained as to the whereabouts of Bin Laden was in December in the Tora Bora cave region of Afghanistan, where he is thought to have been injured following a US bomb attack.