Sheikh Mohammed was questioned by US and Pakistan agents
Pakistani intelligence officials have confirmed that a suspected al-Qaeda leader did claim to have met Osama Bin Laden in December.
Rumours of a recent meeting between the captured Khalid Sheikh Mohammed - said to be the mastermind of the 11 September 2001 attacks on the United States - and Osama Bin Laden have been circulating since he was arrested in Pakistan earlier this month.
Now senior members of Pakistan's InterServices Intelligence (ISI) agency say that Sheikh Mohammed did claim to have met Bin Laden.
But the officials - whose agency questioned the suspect before he was handed over to US authorities - say they are not convinced by Sheikh Mohammed's statements.
The information comes as questioning continues in Pakistan of an Iraqi and two Afghans suspected of having links to Bin Laden's network.
There have also been reports that Bin Laden's sons had also been detained at the end of last week, but US and Pakistani officials have denied these.
The BBC's Paul Anderson in Islamabad says the revelations by the ISI that Sheikh Mohammed broke his silence in initial questioning gives the most recent evidence that Bin Laden is alive.
I don't believe [Sheikh Mohammed] unless he tells us the locations and gives us witnesses
Pakistani intelligence official
But the intelligence services cautioned that the suspect refused to say where the meeting took place.
One official, speaking on condition of anonymity, said of Sheikh Mohammed: "He confirmed he met [Bin Laden] in December.
"I don't believe him unless he tells us the locations and gives us witnesses."
In the unprecedented briefing for foreign journalists, officials also showed an edited video of the 1 March raid in Rawalpindi.
Documents and computers were seized by officers, as well as two men named by US officials as Mustafa Ahmed al-Hawsawi - accused of being an al-Qaeda financier - and Abdul Qadus.
Media reports have said that letters - in Bin Laden's handwriting - were found in the raid, but that has not been confirmed.
There have been further reports of increased operations by Pakistani and US forces on both sides of the Pakistan-Afghanistan border amid tightened security measures.
The search for Osama Bin Laden has intensified in recent days
But a US military spokesman said operations along Afghanistan's eastern border were "nothing special".
Colonel Roger King told reporters at the Bagram air base that soldiers were not just looking for Bin Laden, who has not been seen since he appeared in a November 2001 videotape, though audio recordings purporting to be from him have been released in recent months.
"We have a much broader focus of killing, capturing and denying sanctuary to all terrorists and those who support them," he said.
The three men now being questioned were arrested in an overnight raid in Peshawar, capital of Pakistan's North West Frontier Province, which borders Afghanistan.
An Iranian man and an Arab were detained on similar suspicions on Saturday and are also being questioned.
Officials say Pakistani security forces also raided the Jalozai and Shamshatoo camps housing Afghan refugees near Peshawar on Sunday, but no-one was arrested.
Pakistani and US officials believe many al-Qaeda suspects have crossed over from Afghanistan following the US-led military operations there.