BAGHDAD — Shiite militants and police enraged by massive truck bombings in the northwestern town of Tal Afar went on a revenge spree against Sunni residents there today, killing as many as 60 people, officials said.

The gunmen began roaming Sunni neighborhoods in the city, shooting at residents and homes, according to police and a local Sunni politician.

Ali al-Talafari, a Sunni member of the local Turkomen Front Party, said the Iraqi army had arrested 18 policemen accused of being involved after they were identified by the Sunni families targeted. But he said the attackers included Shiite militiamen.

He said more than 60 Sunnis had been killed, but a senior hospital official in Tal Afar put the death toll at 45, with four wounded.

The hospital official, who spoke on condition of anonymity due to security concerns, said the victims were men between the ages of 15 and 60, and they were killed with a shot to the back of the head.

Police said earlier dozens of Sunnis were killed or wounded, but they had no precise figures, and communications problems made it difficult to reach them for an update. The shooting continued for more than two hours, the officials said.

Army troops later moved into the Sunni areas to stop the violence and a curfew was slapped on the entire town, according to Wathiq al-Hamdani, the provincial police chief and his head of operations, Brig. Abdul-Karim al-Jibouri.