Pakistan said on Friday the United States had not given it any information about the presence of Al-Qaeda leaders, following remarks from United States intelligence chief John Negroponte that they were holed up in Pakistan.
"We have no such information nor has any such thing been communicated to us by any US authority," Pakistan's military spokesman Major-General Shaukat Sultan told the agency.
Washington's ally has always contended that Osama bin Laden and his deputy Ayman al Zawahri could be either side of the rugged, porous border with Afghanistan.
But in an unusually direct statement, Negroponte on Thursday named Pakistan as the centre of an Al-Qaeda web that radiated out to the Middle East, North Africa and Europe.
In a testimony to a Senate Select Committee on Intelligence, Negroponte wrote, without naming bin Laden or Zawahri, that Al-Qaeda leaders are holed up in a secure hide-out in Pakistan.
He said they were rebuilding a network that has been decimated by the capture or killing of hundreds of Al-Qaeda members since the September 11, 2001 attacks on the United States.
Many security analysts suspect that bin Laden is likely to be hiding in Pakistan's tribal regions or neighbouring districts of North West Frontier Province.
There has also been speculation that he may have died, though intelligence agencies say they have not picked up any supporting evidence.
Half-a-dozen audio tapes of bin Laden were circulated in the first half of 2006, but the Al-Qaeda leader last appeared in video tape in late 2004.
Subsequent tapes released were identified as old footage. Zawahri, meantime, has had several tapes released.
On January 5, an audio-tape was posted on the web by Al-Qaeda's media arm al-Sahab, exhorting Somalian Islamists to attack Ethiopia. The authenticity of the tape could not be verified, but correspondents familiar with Zawahri's voice said it was his.
In January last year CIA-operated drone aircraft carried out a missile strike on Pakistan's Bajaur tribal region based on information that Zawahri might be there.
The strike on Damadola village did not kill Zawahri, though it possibly eliminated a handful of Al-Qaeda militants. It killed 18 villagers.
Analysts say Pakistan's denials that it was informed of the strike beforehand were aimed at off-setting domestic criticism of its alliance with the United States.
Last October, around 80 men, some of them young boys, were killed in a missile attack on a madrassa in Bajaur, though this time the Pakistan military said it carried out the operation.
In his testimony, Negroponte acknowledged Pakistan's efforts in the fight against terrorism but said it was also a "major source of Islamic extremism".
He also noted President Pervez Musharraf was aware of the risk of sparking a revolt among ethnic Pashtuns living in the tribal belt straddling the border, as well as the political risks of a backlash from Islamist political parties, especially as national elections are due in Pakistan this year.