Pakistan will pursue murder charges against a U.S. consular employee suspected in the shooting deaths of two armed men possibly intent on robbing him, a prosecutor said Friday.
Rana Bakhtiar spoke after the American appeared in court where judges ordered him to remain in police custody for six days.
The case has sharpened anti-American sentiment in Pakistan.
A third Pakistani was killed in the incident Thursday in the bustling city of Lahore, allegedly after being hit by a U.S. vehicle rushing to the aid of the American.
Police officer Umar Saeed said Friday the American had told officers he had withdrawn money from an ATM shortly before the incident, raising the possibility the two men were following him.
Others Pakistani officers have said the men were likely robbers and both were carrying pistols.
"A staff member of the U.S. Consulate General in Lahore was involved in an incident yesterday that regrettably resulted in the loss of life," the U.S. Embassy in Islamabad said in a statement Friday. "The U.S. Embassy is working with Pakistani authorities to determine the facts and work toward a resolution."
The issue of American diplomats or their security detail carrying weapons inside Pakistan was a hot-button subject last year among certain politicians and sections of the media purportedly worried about the country's sovereignty.
Many Pakistanis regard the United States with suspicion or outright enmity because of its presence in neighboring Afghanistan and regular missile attacks against militant targets in the northwest.
"'American Rambo' goes berserk in Lahore,'" read the headline in The Nation, a right-wing newspaper that frequently publishes unsourced anti-American conspiracy theories.
Western diplomats travel with armed guards in many parts of Pakistan because of the risk of militant attack.
Lahore has seen frequent terrorist bombings and shootings over the last two years, though the city's small expatriate population has not been directly targeted.
The Express Tribune newspaper said in an editorial that it was reasonable for Western diplomats to travel armed, but noted that in America shooting in self-defense can result in a conviction, especially if it can be proved that the accused used excessive force.
Lahore police chief Aslam Tareen said the American was being questioned by the police and may be charged with both murder and illegally carrying a weapon, a Beretta pistol.
"Diplomatic staff usually enjoy a certain type of immunity, but I am not sure about murder," he said. "We will consult the Foreign Office and legal advisers in this regard."
Police officer Riasat Ali said one of the victim's brothers had registered a criminal case against the American, a necessary step for the police to begin an investigation.
Robbers on motorbikes pulling up alongside cars and holding them up is quite a common crime in Pakistani cities.
Americans and other foreigners have also been frequently targeted by Islamist militants.
In the northwestern city of Peshawar in 2008, gunmen shot and killed a U.S. aid worker as he drove to work. Suspected militants also opened fire on the vehicle of the top American diplomat in the city the same year, but she survived the attack.