WASHINGTON: The CIA has pulled its top spy out of Pakistan after threats were made against his life, current and former US officials said, an unusual move for the US and a complication on the front lines of the fight against al-Qaida.

The CIA station chief was in transit Thursday after a Pakistani lawsuit earlier this month accused him by name of killing civilians in missile strikes. The Associated Press is not publishing the station chief's name because he remains undercover and his name is classified.

CIA airstrikes from unmanned aircraft have successfully killed terrorist leaders but have led to accusations in Pakistan that the strikes have killed innocent people. The US does not acknowledge the missile strikes, but there have been more than 100 such attacks this year more than double the amount in 2009.

The lawsuit blew the American spy's cover, leading to threats against him and forcing the US to call him home, the officials said, speaking on condition of anonymity because of the sensitivity of the issue.

CIA officials' ''serious concerns'' for the station chief's safety led to the decision to bring him home, a US official said. A spokeswoman for the spy agency, Jennifer Youngblood, declined to comment.

The Pakistani lawsuit also named CIA Director Leon Panetta and Defense Secretary Robert Gates.

The CIA's work is unusually difficult in Pakistan, one of the nation's most important and at times frustrating counterterrorism allies.

The station chief in Islamabad operates as a secret general in the US war against terrorism. He runs the Predator drone program targeting terrorists, handles some of the CIA's most urgent and sensitive tips, and collaborates closely with Pakistani's intelligence agency, one of the most important relationships in the spy world.

Almost a year ago seven CIA officers and contractors were killed when a suicide bomber attacked a CIA base in Khost, Afghanistan. Six other agency officers were wounded in the attack, one of the deadliest in CIA history.

It's rare for a CIA station chief to see his cover blown. In 1999, an Israeli newspaper revealed the identity of the station chief in Tel Aviv. In 2001, an Argentine newspaper printed a picture of the Buenos Aires station chief and details about him. In both instances, the station chiefs were recalled to the US. – AP