WASHINGTON (Agencies) - The CIAs top spy in Pakistan, who helps oversee drone strikes against militants, has been forced to leave the country amid threats to his life, a US intelligence official said. The official did not provide further details about the abrupt departure of the Central Intelligence Agencys station chief. But the New York Times reported the spy was pulled out after his name - classified as secret - was revealed in a lawsuit by a Pakistani man, who alleges his son and brother were killed in a drone bombing raid. The paper, citing unnamed US officials, also wrote that Pakistans spy service, the Directorate for Inter-Services Intelligence (ISI), may have had a hand in exposing the CIA spy, possibly in retaliation for a legal suit in New York that implicated the ISI chief in the 2008 Mumbai attacks. This exceptional officer - who had already served beyond a regular tour - is returning to the United States after the decision was made that terrorist threats against him in Pakistan were of such a serious nature that it would be imprudent not to act, the official, who spoke on condition of anonymity, told AFP. The intelligence official indicated the threats would not affect the spy agencys bombing war against Al-Qaeda and Taliban figures in northwest Pakistan, which the US government avoids discussing openly. The CIAs mission in Pakistan, including the agencys relentless fight against militants, continues unabated, the official said. Meanwhile, Pakistans top spy agency denied speculation Saturday that it helped unmask the CIAs station chief in Islamabad. A Pakistani intelligence official dismissed any claims of ISI involvement in exposing the CIA official as 'a slur. He declined to offer any comment on the Brooklyn lawsuit and said it was entirely possible Pakistani journalists simply figured out the station chiefs identity on their own. Such unfounded stories can create differences between the two organisations, the Pakistani intelligence official warned. He also said the CIA has not directly accused the ISI of any wrongdoing in the matter. Like other intelligence officials, he requested anonymity because of the sensitive nature of his work and because he is not authorized to speak to media on the record.