The trial has begun in Pakistan of three suspected Islamic militants accused of carrying out a car bomb attack outside the United States consulate in Karachi in June.

The trial began amid tight security in a special anti-terrorism court inside the Karachi prison where the accused men are detained.

All three - Mohammed Imran, Mohammed Hanif and Mohammed Ashraf - have pleaded not guilty to charges of murder, terrorism and the use of explosives.

If found guilty, they could face the death penalty.

The three men, who police say belong to an outlawed militant group, Harkat-ul-Mujahadeen al-Almi, also face separate charges of plotting to assassinate the Pakistani president, General Pervez Musharraf.

Police officer's testimony

Saturday's proceedings began with testimony from a police officer who was injured in the blast.

Agency reports say Deputy Inspector Ali Gauher Soomro told the court he was hit on the shoulders with flying debris when the bomb went off at 11:15 a.m. on June 14.

The consulate bomb killed 12 people

He said 18 vehicles were damaged by the blast, which killed 12 Pakistanis and injured 50 people, but he could not identify which car contained the bomb.

Inspector Soomro was the only witness from a list of 50 compiled by the prosecution to take the stand on Saturday.

Following cross-examination, Judge Ale Maqbool Rizvi adjourned the trial until Wednesday.

'Assassination plot'

Police say President Musharraf survived an assassination attempt because the accused's car bomb failed to detonate as he was being driven past.

It is alleged the same vehicle was later used in the blast outside the US Karachi mission.

A number of foreign and Christian targets have been attacked in Pakistan in recent months.

The authorities blame Islamic extremists angry at the Pakistani Government's support for the US-led war on terror.