Piling up pressure on Pakistan, the US has asked its authorities, particularly ISI, to sever ties with the Haqqani network of Taliban. It demanded strong and immediate action against the outfit, even as it insisted there is no permanent breach in bilateral relations and lines of communication are open. White House Press Secretary Jay Carney told reporters on Friday evening that the Obama administration believes and knows that the Haqqani network was responsible for the attacks on the US embassy in Kabul and the International Security Assistance Force (ISAF) headquarters, and a number of other recent attacks that caused death and injury not only to Afghans but to American soldiers. He said, US knows that the Haqqani network operates from safe havens in Pakistan and that the government of Pakistan has not taken action against these safe havens. Carney said, top US officials, including Secretary of State Hillary Clinton and Chairman of the Joint Chiefs of Staff Admiral Mike Mullen, would continue to have conversations with the Pakistani leadership on this issue.