An American undercover CIA agent, who is facing double murder charges in Pakistan, went on hunger strike in a prison as a protest of "substandard food" and to press for removing of security cameras, officials said.

Raymond Davis, who the Americans claim works for the U.S. consulate in the eastern city of Lahore, had shot dead two Pakistanis on Jan. 27, triggering a serious diplomatic row between the two allies.

U.S. President Barack Obama himself asked for the release of Davis, saying he enjoys diplomatic immunity under the Vienna Convention. The U.S. officials oppose the case to be referred to the court.

But Pakistanis say that Davis is not entitled to diplomatic immunity and the court will decide the issue.

Pakistan's Prime Minister Yousuf Raza Gilani told the parliament on Monday there are differences with U.S. over the issue of Davis and that Pakistan will not accept any pressure.

Officials said that Davis refused to eat in Lahore's Kot Lakhpat jail when food was given to him at lunch time.

The prison officials told the accused that the food is being supplied by the U.S. consulate and Pakistanis have nothing to do with it.

Officials said that the shooter also demanded removal of the security cameras around his barrack, a demand rejected by the jail authorities.

The jail authorities insisted that the cameras have been installed for Davis security and will not be removed.

An emergency meeting of the police and senior officials were summoned Tuesday evening to discuss the situation arising out of Davis strike.

Pakistani intelligence officials confirmed that Davis was on a special secret mission from the CIA.

The Lahore High Court, which is hearing the case of Davis, has given three-week time to the Foreign Ministry to submit a reply about the diplomatic status of Davis.

The court has already stopped the government from the release of the American employee and also ordered ban on his leaving Pakistan.

A petition, seeking ban on Davis leaving Pakistan, was moved in the court. The petition said that the accused is using "undercover" name and his real name is different. The petition said that the court must ensure that Davis does not flee Pakistan on other name.

Gilani said that Pakistan and the U.S. are strategic partners, adding that the Davis case is in the court and the court will decide it.

The Pakistani government is also under tremendous internal pressure not to compromise on the issue.