Defense Minister Chaudhry Ahmed Mukhtar’s remarks on Wednesday that the US had been asked to vacate Shamsi Air Base was the latest salvo as the two countries tussle over their interests in an Afghanistan settlement. The Pakistani government seeks to publicly distance itself from Washington.

“We have been talking to them (on the issue) for some time, but after May 2 we told them again,” Mukhtar told reporters on Thursday. “When they (US forces) will not operate from there (Shamsi Air Base), no drone attacks will be carried out."

According to the sources, the CIA, which has been using Shamsi Air Base in Pakistan since 2004, had to develop other sources, largely based in Afghanistan, to carry out its drone operations targeting Al-Qaeda and its affiliates are allegedly using sanctuaries in the Federally Administered Tribal Areas.

Pakistan had asked US to vacate Shamsi Air Base shortly after the arrest of CIA operative Raymond Davis, and since then CIA is primarily using Afghan soil to execute its drone operations, the sources said.

Sources further said that the CIA is using two airstrips — one at Jalalabad Air Base and the other at Bagaram Air Base in Afghanistan — to carry out its drone operations.