Paramilitary commandos stormed houses in Pakistan's largest city Monday, arresting three men who were charged in last month's deadly bombing at the U.S. Consulate in Karachi.

The three are members of Harkat-ul-Mujahedeen al-Almi, said Maj. Gen. Salahuddin Satti of the paramilitary Pakistan Rangers.

The organization is a splinter group of Harkat-ul-Mujahedeen, or Movement of Holy Warriors, an Al Qaeda-affiliated extremist group whose members fought in Afghanistan and Kashmir, said provincial police chief Syed Kamal Shah.

Dozens of people have been rounded up in connection with the June 14 bombing, which killed at least 12 Pakistanis and injured about 50. However, the three men arrested Monday were the first to be formally charged.

Satti presented the men to reporters, identifying them as Mohammad Hanif, Mohammad Imran and Sheikh Mohammad Ahmed.

"We carried out the operation against America," Hanif told reporters. "We consulted about it and after that, we filled the vehicle with explosives and one companion drove it to the American Consulate."

Police said they believe the three were part of the same group responsible for the May 8 suicide bombing at the Sheraton Hotel in Karachi, in which 11 French engineers and three other people died. Officials say the men also were involved in a previously undisclosed plot to assassinate President Gen. Pervez Musharraf in April.

The men have not been charged in the other incidents, Satti said. Satti added that a dozen other people had been identified as suspects in the bombings. It was unclear if any are among those picked up recently for questioning.

Satti said that so far there was no firm evidence of Al Qaeda involvement in the bombings. Last week, Interior Minister Moinuddin Haider said the government had evidence that Al Qaeda financed the attacks. The statements could not be reconciled.

However, Harkat-ul-Mujahedeen worked closely with Al Qaeda in Afghanistan before the collapse of Taliban rule last year. Five Harkat-ul-Mujahedeen members were killed in a 1998 cruise missile attack on Usama bin Laden's camps in Afghanistan following deadly bombings at U.S. embassies in Kenya and Tanzania.

During Monday's raid, the commandos seized 10 rifles, two Russian-built machine-guns, eight rocket launchers, 63 hand grenades and about 66 pounds of explosives, Satti said.

Investigators also now believe the consulate blast was set off when a suicide bomber drove a car packed with explosives into the consulate compound's wall, Satti added. Police had suspected the bomb was hidden in a car driven by unwitting victims and detonated by remote control as it passed near the consulate.

Satti said authorities believed the car used in the consulate bombing was rigged with explosives as part of a plot to kill Musharraf during an April 26 visit by the president to a political rally in Karachi.

The group tried to detonate the bomb by remote control but it failed to go off, Satti said. The conspirators later retrieved the car and drove it to a garage, where it stayed until it was used in the consulate attack, he said. Satti did not say how police learned of the car's movements.

Satti said one officer of the Pakistan Rangers who was a member of Musharraf's security detail on April 26 has been detained in connection to the assassination plot but has not been charged.

Police said they were also investigating possible links between the bombings and the kidnap-slaying of Wall Street Journal reporter Daniel Pearl in Karachi. Four men are on trial in the Pearl case.

Most of those detained but not charged in the consulate bombings were said to have been members of another militant group, Lashkar-e-Jhangvi. However, sources familiar with Islamic militant movements said it was not uncommon for people to work for more than one underground organization.

Pakistan became a key U.S. ally in the war against terrorism after Musharraf cut ties with the Taliban following the Sept. 11 terrorist attacks in the United States.

Since then, Musharraf's government has been facing a backlash from extremists, who accuse him of selling out to the West.