Baghdad ? Some 1,500 mourners called for revenge Friday as they buried the leader of the Sunni revolt against al-Qaida, who was assassinated by a bomb after meeting with President Bush earlier this month.

An al-Qaida front in Iraq claimed responsibility for the blast that killed Abdul-Sattar Abu Risha, 37, and three companions. A statement posted on the Internet by the Islamic State of Iraq called Abu Risha “one of the dogs of Bush” and described Thursday’s killing as a “heroic operation that took over a month to prepare.”

The statement could not be independently verified, but it appeared on Web sites commonly used by the insurgents. Al-Qaida earlier killed four of Abu Risha’s brothers and six other relatives for working with the U.S. military.

In Diyala province, meanwhile, a bomb exploded near a U.S. military vehicle on Friday, killing four American soldiers, the U.S. command said. They were the first American deaths reported in Iraq since Monday.

Many al-Qaida fighters were believed to have shifted to Diyala after Abu Risha’s tribal fighters helped drive them out of their sanctuaries in Anbar province.

Scores of Iraqi police and U.S. military vehicles lined the route to protect the funeral procession as it followed the black sport utility vehicle carrying the Iraqi-flag-draped coffin of Abu Risha to the family cemetery just west of Ramadi, Anbar’s capital.

“We will take our revenge,” the mourners chanted. “We will continue the march of Abu Risha.”

The sheik was buried one year to the day after he organized Sunni Arab clans into an alliance to drive al-Qaida in Iraq from sanctuaries in Anbar province where the terror movement had flourished since the U.S.-led invasion in 2003.

Lt. Gen. Ray Odierno, the second-highest ranking U.S. officer in Iraq, and several high-ranking government officials attended the funeral, including Iraq’s interior and defense ministers and National Security Adviser Mouwaffak al-Rubaie.

“We condemn the killing of Abu Risha, but this will not deter us from helping the people of Anbar – we will support them more than before,” al-Rubaie declared. “It is a national disaster and a great loss for the Iraqi people – Abu Risha was the only person to confront al-Qaida in Anbar.”

Iraqi officials said the roadside bomb was just outside Abu Risha’s walled compound in view of a guard shack and an Iraqi police checkpoint. That raised suspicion that the killing may have been an inside job, the officials said, speaking on condition of anonymity because the information is sensitive.