The US ambassador to Pakistan has said there is "a strong possibility" Osama bin Laden is hiding in the country's remote tribal regions on the border with Afghanistan.
The United States, Pakistan's spy agency and local police were working closely to track down the al-Qaeda leader, one of the world's most wanted fugitives, Ms Nancy Powell said.
"There is a strong possibility that he might be hiding somewhere in the tribal areas of the country," Pakistani English newspaper The Nationquoted her as saying.
Pakistan's president General Pervez Musharraf has also said that bin Laden could be hiding along the mountainous Pakistan-Afghanistan border.
Pakistan used to be an ally of Afghanistan's former Taliban rulers, who provided shelter to bin Laden.
But after the September 11th 2001 attacks in America, General Musharraf withdrew this support and backed the US-led war on terror which toppled the Taliban government in late 2001.
Pakistan's security agencies have arrested more than 500 Taliban and al-Qaeda suspects since they fled the war in Afghanistan. Many of them were later handed over to the United States.
AP