Baghdad ? Authorities arrested the local leader of a Sunni group that had broken with al-Qaida, sparking a gunfight Saturday in central Baghdad that killed four people and wounded 10, Iraqi officials said.

Adil al-Mashhadani, the head of an Awakening Council group, was detained Saturday along with an aide after a warrant was issued for his arrest, Iraqi military spokesman Maj. Gen. Qassim al-Moussawi said.

The shooting started after Iraqi army and police units served the warrant in Fadhil, a Sunni enclave on the east bank of the Tigris River that was run by al-Qaida until U.S. and Iraqi soldiers regained control in 2007.

Four people — three civilians and a policeman — were killed and 10 people were wounded in the shooting, according to police and hospital officials. They spoke on condition of anonymity because they were not supposed to release information to media.

How the Shiite-led government deals with the Sunni security volunteers, known variously as Awakening Councils or Sons of Iraq, is widely seen as a test of its ability to win the loyalty of disaffected Sunnis — an essential step in forging a lasting peace in Iraq.

It was unclear whether the allegations against al-Mashhadani were based on his purported activities before the Sunni revolt against al-Qaida, during which thousands of Sunnis switched sides.

A U.S. military spokesman, Col. Bill Buckner, confirmed the arrest and said the move was not directed at the Awakening Council.

Fadhil resident Hazim Hussein said about a dozen vehicles loaded with police special commandos entered the neighborhood about 2:30 p.m. and headed toward al-Mashhadani’s home.

About a half hour later, as word of the arrest spread through the neighborhood, heavy gunfire broke out, sending residents fleeing the streets, Hussein said. Police reinforcements rushed to the area and shooting tapered off after about two hours, he said.

“I hurried home to my family, closed the doors. I could hear the sounds of shooting mixed with people shouting. I couldn’t hear what they were saying because of sirens from ambulances and police,” Hussein said.

By nightfall the area was quiet except for the sound of U.S. helicopters patrolling overhead, another resident said on condition of anonymity because he feared for his safety.

The rise of the Awakening Councils is widely seen as a major contribution to the sharp reduction in violence following the U.S. troop surge of 2007.