|Raymond Davis' case has inflamed anti-American feeling in Pakistan [Reuters]
US sources have revealed that Raymond Davis, a US citizen, held in Pakistan on murder charges after a shooting incident, worked as a CIA contractor.
The confirmation, on Monday, of the man's link with the CIA, which had been reported in recent days in Pakistani media, is likely to further strain Washington's ties with Islamabad over the case.
Davis, a former special forces soldier who left the military in 2003, shot two Pakistani men in "self-defence" in what he described as an attempted armed robbery in the eastern city of Lahore.
A third Pakistani, a bystander, died when a car rushing to help Davis struck him.
Davis was carrying a Glock handgun, a pocket telescope and papers with different identifications.
According to a senior Pakistani intelligence official, the two men in the response vehicle that went to aid Davis, killing the bystander, have left the country. The official said the Pakistani government's decision to let them leave was a concession to the US.
Last month's shooting incident has inflamed anti-American feeling in Pakistan and highlighted the countries' uneasy alliance against the Taliban and al-Qaeda.
Further aggravating tensions, the wife of one of the men Davis shot, committed suicide earlier this month. She said she feared her husband's killer would be freed without trial.
Some media organisations, including the Associated Press (AP), learned about Davis working for the CIA last month, immediately after the shootings.
But they withheld publication of the information to avoid putting his life in danger while he was jailed overseas, where at least some protesters were calling for his execution as a spy.
The CIA asked the AP and some US media outlets, including The New York Times and The Washington Post, to hold their stories as the US tried to improve Davis' security situation.
However, the story was broken by The Guardian as a special report, on Sunday.
The US sources said that Davis is a "protective officer" employed as a CIA contractor, but denied rumours that he was involved in covert operations.
His duties were essentially as a bodyguard, to provide physical security to US embassy and consular officers and visiting American dignitaries, US officials who declined to be identified told the Reuters news agency.
Two US sources familiar with the matter, confirmed to Reuters that Davis worked previously on a contract as a security officer for Xe Services, a controversial private contractor formerly known as Blackwater.
Asked during a conference call with reporters about a link between Davis and the CIA, P.J.Crowley, the state department spokesman, said "We will not comment on his particular activity in Pakistan other than to say he is a member of the administrative and technical staff of the embassy and has diplomatic immunity."
A second US official on the call, said that the US embassy in Islamabad notified the Pakistani government on January 20, that Davis was "a member of the administrative and technical staff under the Vienna convention on diplomatic relations."
"From that point ... he enjoyed privileges and immunities against local criminal law, including inviolability of person, inviolability from arrest and detention, and immunity from criminal jurisdiction," the senior US official said.
The official said the United States was trying to work out a diplomatic solution to the disagreement but noted it could take the matter to the International Court of Justice.
Confirmation of a connection between Davis and the CIA came as the US administration renewed its call for Pakistan to recognise what Washington says is Davis' diplomatic immunity and to free him immediately.
However, Crowley said the United States was not considering curtailing economic or military assistance to Pakistan to show its displeasure over Davis' treatment, contrary to earlier reports.
US officials have complained for days that security conditions under which Davis has been held have put his life in grave danger. However, Pakistan said it was taking steps to keep Davis safe.
Prison sources in Lahore said surveillance cameras were monitoring the area where Davis has been locked in a cell isolated from other prisoners.
Outside the Kot Lakhpat jail in Lahore, where protesters have demanded Davis be publicly hanged, some 75 police officers, a team of provincial rangers and vehicles packed with elite forces were deployed.
"We have taken maximum security measures to ensure his protection," said Rana Sanaullah, law minister for Punjab province, where Lahore is located, said.
"They have told us that he is in the safest possible location in Lahore and clearly we hold the government of Pakistan fully responsible of his safety," Crowley said.
Last week, the Lahore high court delayed a hearing on whether Davis had immunity until March 14, prolonging the diplomatic stand-off and stoking concerns for his safety.
US sources denied reports and rumours in Pakistan suggesting that Davis' assailants had some connection with Pakistan's principal intelligence agency, the Inter Service Intelligence directorate, known as ISI.
With co-operation from ISI elements, the US government, including the CIA, has for the past several years been attacking armed fighters in Pakistani tribal areas using missiles fired from remotely piloted drone aircrafts.
Relations between ISI and its US counterparts have deteriorated since an incident last year in which the name of the CIA's undercover station chief in Pakistan was leaked to local media, resulting in the official having to make a hasty exit from the country.