Islamabad: Pakistan Prime Minister's Foreign Affairs Adviser Sartaj Aziz conceded that relations with the US has been under stress for the past three months because of conditions Washington had attached to the funding of F-16 fighter jets sale. The confession was made by the adviser on Thursday while concluding a debate in the Senate on an adjournment motion on the US decision to withdraw proposed subsidy on the sale of F-16 fighter jets to Pakistan, Dawn online reported. The adviser said that Pakistan-US relations had come to a standstill in 2011 because of unfortunate incidents including WikiLeaks and the Abbottabad operation where former Al Qaeda leader Osama Bin Laden was killed. Since 2013, he said Pakistan’s relations with the US had witnessed an “upward trajectory”. “In the past three months, however, this upward trajectory in relations has witnessed a downward slide, as reflected in a decision of the US Congress to block partial funding for eight F-16 aircraft,” he said. Aziz said that the US action might have been caused by concerns raised by Washington on the nuclear issue which had been categorically rejected by Pakistan. The adviser, however, assured the Senate that in view of the importance of the issue, Pakistan is making all-out efforts to finalise the F-16 deal with the US administration. However, senators have termed the US a friend which could not be trusted anymore. They also criticised the US for expanding its relations with India.