Five people, including a child and two Iraqi soldiers were killed in several attacks north of Baghdad, security forces said.

In Samarra, insurgents took on a police rapid reaction force in a firefight that killed the child and one other person, a senior officer said.

Ten Iraqis were killed and 12 wounded late Thursday in a suicide car bomb attack north of Baghdad, a US military source said.

"There was a suicide car bombing outside a home near Balad late Thursday. Ten Iraqis were killed and 12 wounded," said Major Wes Hayes, adding that coalition forces had responded and the Iraqi authorities were now at the scene.

In southern Iraq, Shia cleric Ali Abdel Hussein was killed by gunmen in Basra overnight, his son and a hospital source said.

"Two men armed with pistols shot my father last night," near a mosque in a northern neighbourhood, Mohammed Ali Abdel Hussein said. "I chased them and they shot at me too."

Turkman police General Sabah Bahlul Goralton was assassinated as he left Friday prayers in northern Kirkuk, the second such killing in the ethnically tense oil hub in less than two weeks, police said.

His death came after Kurdish police general Ahmad Saleh al-Baranzanchi was murdered in late May in an attack claimed by al-Qaeda-linked militant group Ansar al-Sunna.

Inhabited by Kurds, Sunni Arabs and Turkmen, Kirkuk was heavily Arabised under the regime of Saddam Hussein.

Kurds now want the oil-rich city to be the capital of their autonomous region, while Arabs complain of harassment since Saddam's fall.

In Baghdad, Iraqi authorities hailed Operation Lightning, a dragnet designed to snare insurgents in the capital, saying Thursday that 700 had been arrested and 28 killed in five days of operations.

But three explosions from a mortar attack shook the capital around midday Friday, with a security source saying the shells had come from a predominantly Sunni area and that one had landed near the Lebanese embassy.

No casualties were reported.

Residents reported some additional mobile checkpoints by interior ministry commandos, but there was little evidence of a massive operation going on, and in many areas of the city, life carried on as usual.

Up to 40,000 army troops and police personnel were to take part in the sweep, but Baghdad streets were filled more often with a motley collection of dusty foreign-built cars than with armoured Humvees or heavily-armed personnel carriers.

Outside Kirkuk, two roadside bombs struck a US patrol early Friday, lightly wounding an unspecified number of soldiers and damaging two Humvee vehicles.