A senior U.S. diplomat says al-Qaida leader Osama bin Laden is alive and in Pakistan and fugitive Afghan Taliban leader Mohammad Omar is possibly hiding in the southwestern city of Quetta.
Speaking to reporters in Pakistan's capital, U.S. Deputy Chief of Mission Gerald Feierstein said the United States "strongly believes" Osama bin Laden is operating from Pakistan's tribal areas near the Afghan border.
He also said U.S. officials believe Quetta has become the control and command center of the Taliban leadership. He said militants move freely across the border with Afghanistan and are responsible for attacks on U.S. and Afghan forces.
Pakistani Interior Minister Rehman Malik disagrees, saying the U.S. claims are "mere speculation."
"We have categorically told them that [the militants] are not in Quetta. And if they have any real-time information, they should give it to us, and we will take action," he said.
While rejecting the U.S. claims, Pakistani foreign ministry spokesman Abdul Basit warned against any drone attacks in the region.
"Baluchistan is not FATA. And so we are in touch with the U.S. on this and we have conveyed our concerns. And we will continue to raise our concerns," he said.
U.S. unmanned aircraft, known as drones, have increased attacks recently on suspected al-Qaida and Taliban bases in Pakistan's Federally Administered Tribal Areas (FATA).
Officials say such strikes are believed to have killed several high-level militant commanders, including former Pakistani Taliban leader Baitullah Mehsud.
There are widespread fears in Pakistan the drones could be turned to focus on suspected Taliban hideouts in the southwestern province of Baluchistan, where Quetta is the capital.