Raymond Davis, a CIA contractor accused of of killing two Pakistani men, was formally charged with two counts of murder Wednesday, a police official said.
According to Davis, the January 27 shooting occurred after two men attacked him as he drove through a busy Lahore neighborhood, the U.S. Embassy says.
The case has heightened tensions between Washington and Islamabad.
The United States has been seeking the release of Davis on the grounds that he has diplomatic immunity.
But a high court in Pakistan refused Monday to decide whether the CIA contractor has diplomatic immunity, sending the case back to a lower court, the official Associated Press of Pakistan reported.
The lower court has already ruled that Davis does not enjoy protected diplomatic status because neither he nor the Pakistani government has provided documents proving that he does.
U.S. officials originally said Davis was a diplomat and later revealed that he is a CIA contractor, intensifying the already highly charged situation.
Pakistan is a key U.S. ally in efforts against al Qaeda and the Taliban in neighboring Afghanistan, and the shooting deaths have outraged many Pakistanis.