Pakistan's civilian government reiterated on Thursday it had "no evidence" that Al-Qaeda mastermind Osama bin Laden was in the nuclear-armed Muslim country, as Washington has charged.
"Al-Qaeda and Taliban have threatened Pakistan, attacked our security forces, killing innocent civilians and targeted our leadership," said Information Minister Qamar Zaman Kaira in a statement.
"We are therefore combating terrorism in our own interest. We do not want our efforts to be undermined by hypothetical assumptions," he added.
The statement from his office said there "is no evidence that Osama bin Laden is present in Pakistan" and that "those making claims of his presence in the country should provide valid proof of it".
Last week, a US counterterrorism official told AFP one of bin Laden's sons "may be dead" following reports he was likely killed by a US missile strike in Pakistan earlier this year.
It was unclear whether Saad bin Laden was close to the location of his father, who is believed to be hiding in the rugged mountainous tribal belt along the Afghanistan-Pakistan border, when he died.
The last audio message said to be from Osama bin Laden and released by Al-Qaeda was aired in June on Al-Jazeera when he accused US President Barack Obama of following George W Bush's policy in "antagonizing Muslims."
And although Obama has vowed to hunt down bin Laden, the Al-Qaeda leader has eluded capture.
Washington has put Pakistan at the heart of the fight against Al-Qaeda and the Taliban as part of a new war strategy ordering an extra 21,000 troops to neighbouring Afghanistan in a bid to stabilise the country for August elections.
In March, Obama said multiple intelligence estimates warned Al-Qaeda was actively planning attacks on the US homeland from "its safe-haven in Pakistan."
Since the September 11, 2001 attacks, Al-Qaeda and its allies moved into the remote Pakistani frontier areas, Obama said.
"This almost certainly includes Al-Qaeda's leadership: Osama bin Laden and Ayman al-Zawahiri," he added, urging Pakistan to become a stronger partner in flushing the militants out of their safe havens.