Vowing revenge and beating their chests, more than 300,000 Shiites marched Sunday behind the rose-strewn coffin of a beloved cleric assassinated in a car bombing. The FBI said it would join the investigation into the Najaf (search) bombing, which killed 125 people.
Iraqi police said the bomb that exploded after noon prayers Friday at the vast Imam Ali mosque (search) contained the equivalent of 1,650 pounds of TNT.
In Washington, FBI (search) spokesman John Iannarelli said the bureau will join the investigation in Najaf.
He said the bureau will provide forensic analysis of the evidence and said it was still working out what other assistance the FBI, which has agents assigned to the region, would provide.
The call for the FBI to join the investigation represented a shift after U.S. authorities had taken a hands-off approach -- out of deference to the sacredness of the mosque, which houses the tomb of the Prophet Muhammad (search)'s son-in-law, Ali. Iraqi police say 19 suspects arrested so far may have links to Al Qaeda.
Many Shiites have blamed Saddam Hussein (search) loyalists for the blast, but it has also stoked anger at the U.S. occupation forces among some faithful, who say the Americans have not provided security since Saddam's fall.
With a 110-mile march from Baghdad to the holy city of Najaf, Shiites honored Ayatollah Mohammad Baqir al-Hakim (search), a moderate cleric and once-exiled opponent of Saddam. A three-day mourning period began early Sunday with services at the al-Kadhimiya shrine in the capital.
Marchers followed a flatbed truck carrying a symbolic coffin: Authorities said they found only the cleric's hand, watch, wedding band and pen in the wreckage of the enormous blast.
Halfway along the route, at Karbala, the second-holiest Shiite city after Najaf, 3,000 mourners gathered at a shrine to await the procession. They prayed, beating drums and flagellated themselves with chains as the ayatollah's coffin and the huge procession neared. His funeral is planned for Tuesday in Najaf, his birthplace.
"Our revenge will be severe on the killers," read one of the many banners carried by mourners. Red and white roses were laid on the coffin and a large portrait of al-Hakim placed in front of it.
The U.S.-led Coalition Provisional Authority said Najaf Governor Haider Mehadi asked the FBI to join Iraqi police in the investigation, and that the American investigators would be traveling to Najaf shortly.
FBI agents are leading the investigations into both the Aug. 7 bombing of the Jordanian embassy in Baghdad and attack on the U.N. headquarters 12 days later.
Iraqi police told The Associated Press they have arrested 19 men -- many of them foreigners and all with admitted links to Al Qaeda -- in connection with the blast.
In Najaf, Maj. Rick Hall, spokesman for the 1st Battalion, 7th Marines said the death toll now stood at 125 with 142 wounded, some seriously. He also said the Marine transfer of the south-central territory around Najaf to an international force led by Poland, set for this week, had been put on hold.
"We now want to stay here and assist as much as possible," Hall said.
He said U.S. forces had two men in custody that were handed to them by Iraqi authorities. "We are questioning them, but we are leaning toward releasing them," Hall said, adding that the involvement of Al Qaeda members in the Friday explosion was "an option we are looking at."
Hall denied reports that the Marines would patrol around the mosque, citing Islamic sensitivities to having non-Muslims in or around the country's holiest Shiite shrine. He said U.S. forces had offered Marine patrols of the area to the interim Governing Council in Baghdad and religious leaders in Najaf. An answer was expected in the next day or two, he said.
Police detained two Iraqis and two Saudis shortly after the Friday bombing, and they provided information leading to the arrest of 15 other suspects, said a senior police official in Najaf, speaking on condition of anonymity.
Two Kuwaitis and six Palestinians with Jordanian passports were among the suspects, the official said. The remainder were Iraqis and Saudis, the official said, without giving a breakdown.
"They are all connected to Al Qaeda," the official said.
A Saudi Foreign Ministry official, speaking Sunday on condition of anonymity, rejected reports that Saudi citizens were involved.
"The Saudi government would like these sources to reveal the information they have and present it to the Saudi government instead of making statements without any proof," the official told the government-operated Saudi Press Agency.
Hall said American forces had no access to those in Iraqi police custody, but said he had heard numbers ranging from nine to 19.
Police said there were similarities between the mosque bombing and the recent attacks at the Jordanian Embassy and United Nations.
Iraqi police said the bomb at the Imam Ali Shrine -- the burial place of the son-in-law of the Prophet Muhammad -- was made from the same type of materials used in the previous bomb attacks.
The bombing in Najaf added urgency to U.S. plans to create a 7,500-strong Iraqi militia that would eventually take over civil defense duties in the country's cities. Gen. John Abizaid, the head of U.S. Central Command, announced plans to create the new militia, called the Iraqi Civil Defense Corps, on July 21.
A day before the bombing, commander of U.S. forces in Iraq, Lt. Gen. Ricardo Sanchez said mobilizing the Iraqi militia -- rather than bringing in more U.S. or coalition troops to Iraq -- was the key to stabilizing the security situation in the country.
A key figure in the U.S.-picked Governing Council wrote in a Washington Post op-ed column Sunday that the United States needed to include Iraqis in their own security.
"You have the firepower and mobility, we have the local knowledge and intelligence. Only if we work as true partners will we achieve the victory that is so vital to both our countries," he wrote.