Kerry capped his visit with a statement that he expected a resolution "in the next few days." That timeline was scuttled when lawyers for the Pakistani government, which had indicated that it would support Davis's immunity claim at the Thursday hearing, said they needed more time to prepare a position.
The dispute over Davis, a former Special Forces soldier who U.S. officials say was an embassy staff member, has deeply rattled the strategic relationship between Pakistan and the United States. The White House has postponed a meeting of Afghan, Pakistani and American officials planned for next week in Washington, and Congress is threatening cuts in funding to Pakistan, the recipient of billions of dollars in U.S. economic and military aid.
But Pakistan's unpopular civilian government is also under enormous pressure - from an intensely anti-American public, religious parties and the political opposition - not to free Davis.
Davis has said that he acted in self-defense when he fatally shot two Pakistanis on Jan. 27, an assertion rejected by police. Pakistani media have questioned why Davis was armed and what his duties were in Lahore, the capital of Punjab province.
The U.S. ambassador to Pakistan, Cameron Munter, said in a statement Thursday that the United States was "disappointed" that the government did not certify immunity for Davis.
Echoing Kerry, Munter apologized for the "tragic" incident in Lahore, in which a third, uninvolved man was also killed after being hit by a U.S. consulate vehicle that was coming to Davis's rescue.
The United States has made conflicting statements about Davis's job, and a lawyer for the Punjab provincial government, Khawaja Haris Ahmed, pointed to those discrepancies in court Thursday to argue that Davis does not have immunity.
The next hearing in the case is scheduled for March 14.
Sahi, a special correspondent, reported from Lahore.