British Prime Minister Gordon Brown said on Thursday the continued presence of Al Qaeda terrorists in Pakistan requires Islamabad to take primary responsibility for fighting them.
"They have responsibilities upon themselves," Brown told senior British MPs.
"If they are going to make sure the government can hand the legitimacy that is necessary, they've got to deal with the terrorist problem themselves, but we also are ready to help them if that's what they want us to do."
"We can see the flow, unfortunately, of terrorists from Pakistan to Afghanistan, and we know that if we are dealing with the Al Qaeda problem we are dealing with a problem that exists in Pakistan as well as Afghanistan," the British leader said.
Answering questions at a hearing of the chairpersons of British parliamentary committees, Brown welcomed a two-month review of Afganistan and Pakistan policies announced by the Obama Administration.
He said he had met the US Special Representative Richard Holbrooke in the last few days to discuss the review.
"It is important to recognise that, first of all, we have got to take action against the new type of threat that we have got. Secondly, that means taking action on the borders, working with the Pakistani authorities, to deal with the terrorist problem there," Brown said.
However, he said, British policy in Afghanistan must complement military action in order to ensure the country's social and economic development and strengthen army, police and local government.
He said he expected a meeting of the North Atlantic Treaty Organization (NATO) on April 3 and 4 to come up with "a new set of proposals about how we deal with the evolving situation in Afghanistan and Pakistan".