ISLAMABAD (Agencies) - A senior US diplomat intervened Sunday to end the deadlock between Pakistan's governing coalition partners over the reinstatement of deposed judges that seriously threatens their month-old alliance. US Assistant Secretary of State for South and Central Asian Affairs Richard Boucher Sunday met former premier Nawaz Sharif in London, where the alliance partners had been holding inconclusive talks on the course to be followed for the return of the judges, including Chief Justice Iftikhar Chaudhry. The meeting between Boucher and Sharif took place at the request of Washington, and they discussed 'Pakistan's political and security situation', TV news channels cited Nawaz's personal secretary Imran Khwaja as saying. According to an American news agency, Zardari and Sharif also met separately Sunday with US Assistant Secretary of State Richard Boucher, who was visiting London at the time. Elizabeth Colton, spokeswoman for the US Embassy in Islamabad, confirmed the meetings. She did not reveal what the meetings entailed. But in response to reports that they were on the topic of the judges, Colton said: "The restoration of judges is Pakistan's issue to solve. It is not for the United States to prescribe solutions." Boucher's meeting with Nawaz Sharif started at 10 am British local time and lasted till 1 pm. According to BBC, a Pakistani reporter outside Nawaz's residence in London said that Boucher went in and another American official was with him. Journalists tried to talk to the Boucher but they could not succeed. It is believed that Boucher came here to try to remove the deadlock over judges issue. APP adds: The efforts to bring about consensus on the thorny issue of the restitution of judiciary took a new turn when American deputy Secretary of State for South Asia Richard Boucher held a meeting here on Sunday with PML-N leaders Nawaz Sharif and Shahbaz Sharif. The State Department official landed in the British capital early morning on his way home from a Bangladesh visit and went into talks with the PML-N leaders in an effort to end the stalemate. Party sources said the meeting discussed various aspects of the issue relating to the reinstatement of the sacked Supreme Court judges after the earlier rounds of talks between the ruling coalition partners had failed to break the impasse. The sources said that America is keen to see amicable settlement of the judiciary issue in such a way that all the stakeholders are satisfied. Boucher was also meeting the PPP Co-Chairperson Asif Ali Zardari in his short stay in London. APP adds: 'The restoration of judges is Pakistan's issue to solve. It is not for the United States to prescribe solutions', said a statement issued by Elizabeth Colton, spokesperson, US Embassy here Sunday. 'Our interest is in supporting Pakistan's democratic transition and continuing our common struggle against the Taliban and Al-Qaeda, she added. About Richard Boucher's meetings with Pakistani leaders in London, the spokesperson said, over the weekend, enroute from Bangladesh back to Washington, US Assistant Secretary of State for South & Central Asia (SCA) Richard Boucher stopped in London to consult with his UK foreign office counterparts. While in London on Sunday, Assistant Secretary Boucher also took the opportunity to meet with Asif Ali Zardari of the Pakistan People's Party and Nawaz Sharif of the PML-N, who were both in London. Theses meetings were part of Assistant Secretary Boucher's regular interactions with a wide range of Pakistani political leaders.' There are completely unfounded reports that he was meeting over the judges' issue, the spokesperson added.