Baghdad, Iraq ? A suicide car bomber killed four people and slightly wounded a deputy interior minister Saturday in the second such attack on a senior Iraqi official in Baghdad of the week.

Both attacks were claimed by the same al-Qaida-linked group.

A statement by the group posted on the Internet said the bomber Saturday came from Syria, supporting long-standing U.S. claims that foreign fighters are involved in insurgent attacks in Iraq.

Fighting flared anew in the Shiite holy city of Najaf and nearby Kufa between American soldiers and the Shiite militia of Muqtada al-Sadr, with bursts of heavy mortar and machine -gun fire heard about midnight. A live report on Al-Jazeera television from its correspondent in Najaf was punctuated by strong explosions near a downtown hotel.

More than 20 tanks and hundreds of soldiers moved Saturday night into Kufa after pounding the city with artillery, said CNN, which has a reporter accompanying the troops. It said the troops killed 16 suspected insurgents and seized a large cache of weapons at a mosque.

Late Saturday, a U.S. patrol moved into the center of another Shiite holy city, Karbala, but found no sign of al-Sadr’s militia. Residents told the soldiers that the militiamen fled the area the previous night.

Saturday’s suicide blast outside the home of Abdul-Jabbar Youssef al-Sheikhli, the deputy interior minister in charge of security, hurled two cars onto the front lawn of his house. Police fired warning shots to disperse distraught bystanders who scuffled with them after the attack.

Al-Sheikhli was injured in the forehead and right arm, said Hassan Hadi, a Health Ministry official.

Bodyguards fired on the bomber’s car as it approached, said Brig. Gen. Mark Kimmitt, the chief U.S. military spokesman in Iraq. Three bodyguards and a woman were killed as well as the bomber, he said. Earlier, Iraqi authorities said four police died.

Warning to U.S.

Al-Sheikhli belongs to the Shiite Muslim Dawa party, which lost a prominent member in another fatal car bombing on Monday. The president of the Iraqi Governing Council, Dawa member Izzadine Saleem, was killed along with at least six other people near the headquarters of the U.S.-run coalition in the capital.

The Monotheism and Jihad Group, which claimed responsibility for Saleem’s death, said it carried out the attack Saturday as a warning to the United States and its allies.

“They will not be safe from the hand of God’s retaliation, then the mujahedeen’s, and that they should be ready,” said the statement, posted on an Islamic Web site.

It said “martyr” Ahmed el-Shami Aby Abdel Rahman, from Qamishli, Syria, “drove a car bomb to take (al-Sheikhli) to hell.”

The group’s leader is believed to be Abu Musab al-Zarqawi, a Jordanian wanted by the United States for organizing al-Qaida operations in Iraq and suspected of beheading American civilian Nicholas Berg.

In Najaf, south of Baghdad, fighting broke out Saturday between U.S. forces and al-Sadr’s militia near the city’s police directorate and the governor’s office. At least 10 people were injured in the Saturday clashes, which erupted again about midnight, according to Radhi Kadhim, a nurse at al-Hakim Hospital.

Residents of Najaf reached by telephone said they could hear the sounds of automatic weapons fire and explosives late Saturday coming from Najaf’s twin city, Kufa, but efforts to reach anyone there were unsuccessful.

Americans killed

Also Saturday, the military said a U.S. soldier was killed and three others from the U.S. Army’s 1st Armored Division were wounded in an attack on their vehicle south of Baghdad, and a Marine died in a nonhostile incident.

It said the soldiers’ vehicle was “ambushed by a vehicle-borne improvised explosive device” in Mahmoudiyah, 30 kilometers (20 miles) south of Baghdad. The statement did not say when the attack occurred.

The military said the Marine, assigned to the 1st Marine Expeditionary Force, died Friday near Camp Fallujah, west of Baghdad, while “conducting security and stability operations.”