ISLAMABAD: The future of quadrilateral mechanisms is in jeopardy after the killing of Afghan Taliban Ameer Mulla Akhtar Mansour as Pakistan is still not willing to resume the Afghan peace process, official sources told Daily Times. Sources revealed that the US has been requesting the Pakistan military and civil leadership to resume the Afghan peace process, but Pakistan refused to host or attend the meeting as it wanted some assurances in writing from the US. It showed the trust gap, following the American drone strike that killed Mullah Mansoor, which had shattered the Pakistan’s confidence. A four member US delegation under the leadership of Senator John McCain is expected to visit Pakistan on 2nd July. Other members are Republican house member Ric Davis , Senator Lindsay Graham and Senator Joe Donnelly. All members will meet the Advisor to Prime Minister on Foreign Affairs Sartaj Aziz. They are also expected to request a meeting with Chief of Army Staff General Raheel Sharif. The purpose of this visit is to convince Pakistan to resume the Afghan peace process. The US delegation will also visit Afghanistan and meet Afghanistan’s leadership, sources said. Pakistan has now a clear stance regarding the Afghan peace process. “We made it clear to US and Afghan government officials that the process cannot go forward till the principles agreed in the quadrilateral group meetings are followed, which forbade drone strikes against those Afghan Taliban who were ready to talks. Mullah Akhtar mansour was engaged in this regard, and Richard Olson had assured us the US would not carry out drone strikes but this commitment was broken.” Sources disclosed that US ambassador in Pakistan David Heal , when met army chief general raheel sharif at GHQ on his request , apologized to General Raheel Sharif for the drone strike and apologised to the COAS. He sent report to Washington in this regard as well.