U.S. Secretary of State Hillary Clinton called Pakistani Prime Minister Yusuf Raza Gilani Saturday to express condolences once again over the Pakistani soldiers killed in NATO attacks and reiterated "America's respect for Pakistan's sovereignty."

"She once again expressed condolences to the families of the soldiers and to the Pakistani people for the tragic and unintended loss of life in Mohmand last weekend," the State Department said in a statement.

"She reiterated America's respect for Pakistan's sovereignty and commitment to working together in pursuit of shared objectives on the basis of mutual interest and mutual respect," it added.

A total of 24 Pakistani soldiers were killed and 13 others injured on November 26 as NATO fighter jets and helicopters attacked Pakistan's Mohmand Agency tribal region which borders Afghanistan. Enraged by the incident, Islamabad shut down NATO's supply line into Afghanistan and boycotted an international conference in Bonn on Afghanistan.

Pakistan also asked Washington to vacate a key airbase in the country's southwest Balochistan province in 15 days, while turning down a US invitation to jointly investigate the cross-border attack.

US-Pakistan relations have already been strained since May when US special forces killed al Qaida's No.1 leader Osama bin Laden, not far from Islamabad, without asking for permission from Pakistani authorities.