Islamabad:  The United States hopes Pakistan will soon agree to re-open supply routes to Nato troops in Afghanistan, a US official said yesterday, after a Senate panel threatened to cut aid to Islamabad over the standoff.

Pakistan closed the supply routes, seen as vital to the planned withdrawal of most foreign troops from Afghanistan before the end of 2014, in protest against last November's killing of 24 Pakistani soldiers in a Nato air attack along the Afghan border.

"Talks are ongoing and we hope to reach a resolution soon," the US official told Reuters.

Nato has been seeking to compensate for the lack of access in Pakistan with shipments of war supplies via Afghanistan's other neighbours, but those routes are more expensive.

A Western official said fees for use of the routes which Pakistan is demanding are under discussion in talks currently focused on technical issues. US President Barack Obama said on Monday that he felt the United States and Pakistan were making "diligent progress" on a deal.

Obama, who spoke briefly with Pakistani President Asif Ali Zardari on the sidelines of the Nato summit in Chicago, said he told Zardari that Pakistan needed to be part of the solution in Afghanistan. That call for greater Pakistani cooperation has often been made since the country joined the United States' global war on militancy after the Sept. 11, 2001, attacks.

Islamabad often complains that US officials, especially Republican senators and congressmen, advocate a hardline, naive approach to Pakistan which fuels anti-American sentiment and makes cooperation more difficult.