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A Pakistani court delayed a hearing Thursday on whether a U.S. Embassy worker detained for fatally shooting two Pakistani men has diplomatic immunity. The decision came a day after a visiting U.S. senator pressed for a quick resolution to avert a meltdown in the countries' relations.

The chief justice of the Lahore High Court agreed to a government request for a three-week delay to allow it more time to prepare its position on the issue of immunity. The hearing was rescheduled for March 14.

The case is straining Washington's already troubled relationship with Pakistan, a key partner in the war in Afghanistan and in battling Al Qaeda and other Islamic militant networks.

The U.S. says Raymond Davis shot two armed Pakistani men in self-defense as they tried to rob him, and that his detention is illegal under international agreements covering diplomats. Pakistani leaders, fearful of stoking more outrage in a public already rife with anti-U.S. sentiment, have said the matter is up to the courts to decide.

Pakistan's federal government also will submit an opinion on the matter and has asked the court for more time to prepare, Deputy Attorney General Naveed Inayat Malik said. He did not elaborate.

It was not immediately clear why the government needed the extra time. Government officials had previously said that they were ready to issue their findings to the court at Thursday's hearing, but Pakistan's authorities have at times appeared divided on how to handle the Davis case.

Chief Justice Ijaz Chaudhry said he could not hand down a decision before getting the government statement.

"How can I issue any order when I do not have anything from the federal government regarding his diplomatic immunity?" Chaudhry asked. He did not say how long he expected a ruling to take after receiving the needed statements.

On Wednesday, U.S. Sen. John Kerry said he was hopeful that Washington and Islamabad can make progress "in the next few days" toward resolving the dispute. Kerry held two days of talks with senior Pakistani government officials and opposition powerbrokers.

"Now everybody has to work in goodwill to make the words mean something," Kerry told reporters before boarding a plane in the Pakistani capital.

After the hearings Thursday, U.S. Ambassador to Pakistan Cameron Munter expressed disappointment at the Pakistani government's failure to certify that Davis has immunity, while again expressing regret over the deaths.

"Senator Kerry's visit to Pakistan manifested our intention to work with the government of Pakistan to resolve this issue," Munter said. "As the senator said during his visit, we want to work together as two countries that have a common interest in the same goal and find a path forward."

Davis' case is working its way through Pakistan's judicial system on several tracks. Police say they plan to ask that Davis be charged with murder.

Also Thursday, a judge in a separate court extended Davis' judicial custody for 14 days in a case dealing with his possession of a gun. The U.S. position has been that Davis has permission from the Americans to carry a firearm, but that it was a "gray area" if Pakistan's government allowed it.

Davis, a 36-year-old Virginia native, has been held in a Pakistani jail since his arrest in Lahore, eastern Punjab province's main city, immediately after the Jan. 27 shootings. His name has also been put on a list barring him from leaving Pakistan, Malik said.

Much of the confusion over Davis' status lies in his background.

The U.S. says Davis was part of the embassy's "administrative and technical staff," which means he might have been involved with security, but Pakistani media have focused on him being a former Special Forces soldier who runs an American "protective services" company with his wife.

Although the U.S. says he's an embassy employee, he apparently had been attached for a while to the consulate in Lahore, further adding to the confusion about his status since consulate employees do not always get the same level of diplomatic protection as embassy staffers.

On Thursday, the top legal official for Punjab province maintained that Davis did not qualify for immunity because of his connection to the Lahore consulate. Though Davis was holding a diplomatic passport, "it does not mean that he enjoys immunity from criminal prosecution," Punjab Advocate General Khawaja Haris said.

The AP also obtained a photocopy of an ID and a salary document that Davis apparently gave Pakistani authorities showing that he was scheduled to be paid for "overseas protective sec. svcs." The ID card identifies him as a Defense Department contractor.