The US has suspended all high-level dialogue with Pakistan to pressure Islamabad to release an American diplomat detained on possible murder charges,as ties between the countries have come under severe strain over the issue. The case of Raymond Allen Davis,who fatally shot two Pakistanis who threatened him from a motorcycle last month,may scuttle a proposed tri-nation summit between US,Afghan and Pakistani leaders scheduled to be held here on February 24,The Washington Post reported. Pakistans Dawn reported that President Asif Ali Zardaris visit to Washington in March,scheduled after the summit,and the next round of US-Pakistan strategic dialogue,could also be frozen. To convey its displeasure at the treatment of the diplomat,Secretary of State Hillary Clinton cancelled a meeting over the weekend with Pakistans Foreign Minister Shah Mehmood Qureshi in Munich,the Post reported. The Obama administration has twice summoned Pakistans envoy to the US Hussain Haqqani to the White House to stress Daviss diplomatic immunity and demand his release. The message was repeated by the US Ambassador in Islamabad,Cameron Hunter,in his meeting with President Zardari. The State Department has said Davis,36,holds a diplomatic passport and is a member of the technical and administrative staff at the Islamabad embassy,entitled to full criminal immunity in accordance with the Vienna Convention. The US Congress has said that Pakistan should resolve the issue at the earliest,or it could impact other bilateral initiatives including massive US aid,without which Pakistan would collapse. Davis was arrested in Lahore last month and produced before the local High Court which has extended his detention for another eight days. The US embassy said it was given no notice of the hearing,no attorney was present,and that Davis was not even provided with an interpreter. He was denied due process and a fair hearing, a State Department statement said. His continued detention is a gross violation of international law. Quoting Pakistani officials,the Post said that the countrys government was divided over the case while the Foreign Ministry was pushing Daviss diplomatic immunity,other arms of the government had latched on to the issue to make a statement to the US,against which there is deep mistrust in the establishment and resentment on the streets. A new twist to the case,the Post said,had been provided by a Pakistani intelligence official who had claimed that the two men Davis killed were not,as he had said,armed robbers,but intelligence agents assigned to trail him. The official said the agents had intended to frighten Davis because he had crossed an undefined red line.