Punjab Prosecutor Abdus Samad says the judge also has ordered that the Pakistani government clarify whether or not the man enjoys diplomatic immunity, as the US says he does, AFP reports.

The US says the American, identified by Pakistanis as Raymond Davis, shot two Pakistanis dead in late January in self-defense because they were trying to rob him.

Washington insists his detention is illegal under international agreements covering diplomatic immunity.

The case has inflamed the fractious relationship between Islamabad and Washington, which are allies in the war against extremist insurgents in Afghanistan.

On January 27, Raymond Davis, a staffer at the US consulate-general in Lahore, shot dead two Pakistani men who he said were trying to rob him in broad daylight on the streets of the city.

A third Pakistani was run over and killed by a US consular vehicle coming to aid Davis, who was instead taken into Pakistani police custody.

But in what has become a political time-bomb, the government in Islamabad is under enormous domestic pressure to see Davis go on trial and local lawyers argue that diplomatic immunity can be waived for grave crimes.

The deaths sparked protests in Pakistan, where the alliance with Washington is hugely unpopular and anti-American sentiment runs high, fuelled by US missile attacks on extremists in the northwest.

The wife of Mohammed Faheem, one of the two men shot dead by Davis, committed suicide on Sunday by taking poison. Doctors said that before she died, Shumaila Faheem told them she feared Davis would be released without trial.

“We want blood for blood,” she had told Pakistani television.

Davis has previously been held on an eight-day police remand. The previous remand period expired today.