Pakistani officials say security forces armed with fresh intelligence are tracking about 40 suspected Taleban and al-Qaida insurgents thought to be hiding out in the tribal areas bordering Afghanistan.
Officials in Pakistan say the manhunt was instigated after Afghan President Hamid Karzai provided a series of leads about key Taleban and al-Qaida figures during his visit to Pakistan earlier this month.
The Afghan delegation also shared intelligence information regarding the suspected hideout of Taleban leader Mullah Omar inside Pakistan.
But speaking to reporters, Pakistan's Foreign Ministry spokeswoman Tasneem Aslam says those reports have not proven reliable.
"Some information was provided about Mullah Omar's whereabouts. Some of that information has already been checked and it's not correct," she said.
Not included on the Afghan list, she says, is al-Qaida terrorist Osama bin Laden.
The Saudi-born militant is widely believed to be hiding out in the rugged mountains dividing Pakistan and Afghanistan.
Aslam repeated long-standing Pakistani objections to the claims.
"There is no evidence that Osama bin Laden is here or was here or where he is. If we knew where he was he would be caught," she said.
U.S. and Afghan officials also claim hundreds of Taleban insurgents have established bases inside Pakistan.
Islamabad says it has taken all possible measures to prevent illegal cross border movements, including deploying more than 70,000 troops to the area.
The issue is expected to take center stage during President George Bush's trip to Pakistan later this week.
President Bush is scheduled to arrive March 4, after touring neighboring India.
Pakistan remains an ally in the U.S. led war on terror. But Washington is reportedly seeking greater assurances from Islamabad that border security will be tightened.