ISLAMABAD: US Ambassador to Pakistan Richard Olson called on Prime Minister Nawaz Sharif on Wednesday at the Prime Minister House and briefed the premier on the Border Security Agreement (BSA) recently signed between US and Afghanistan and assured that Pakistan's reservation, a senior government source told Dawn.

Newly sworn in Afghan President Ashraf Ghani had yesterday signed the long-delayed security pact allowing American troops to stay in Afghanistan after the end of the year.

Under the terms of the agreement, 12,000 foreign military personnel are expected to stay after 2014 when the combat mission of the US-led North Atlantic Treaty Organisation (Nato) force in Afghanistan ends.

Also read: Pak-Afghan ties: the road ahead

The source also said that today's meeting was a follow-up after the premier's talk with US Vice President Joe Biden in New York on the sidelines of the United Nations General Assembly.

A spokesman for the PM House said the two discussed bilateral relations.