Gunmen attacked a checkpoint north of Baghdad on Thursday morning, killing 10 Iraqi security forces -- six Iraqi soldiers and four police, an official with the Salaheddin Joint Coordination Center said.

According to the official, a large number of gunmen fired on the joint checkpoint in al-Dour, about 90 miles (140 km) north of Baghdad, at 6:30 a.m. (10:30 p.m. Wednesday ET).

About 20 miles south of Baghdad, an oil pipeline was burning in al-Musayyib, following a rocket-propelled grenade attack by insurgents Wednesday night, a Hilla police spokesman said.

Gunmen shot at firefighters as they rushed to the scene, wounding two of them. Police arrived a short time later and engaged the insurgents in an hourlong gun battle, the spokesman said.

At least 38 Iraqis died in violence Wednesday. They were among more than 400 Iraqis killed amid sectarian fighting that ripped through the tense country after a revered Shiite shrine in Samarra was bombed on February 22, setting off reprisals against Sunnis that led to retaliation against Shiites.

U.S. and Iraqi officials are trying to persuade local and regional leaders to work quickly and put a lid on the hatred, fearing that the tit-for-tat bloodshed will deteriorate into a civil war.

Iraqi political leaders will meet Thursday to discuss the security situation and how to cobble together a national unity government, said Ridha Jawad, a spokesman for the Shiite-led United Iraqi Alliance, which won the most seats in December's parliamentary election.

One issue that may be raised is the key nomination of a prime minister by the alliance. Last month, the coalition voted to nominate transitional Prime Minister Ibrahim al-Jaafari to the post.

The winning party gets first crack at nominating a prime minister, but its choice must win approval in the parliament. Political leaders are trying to agree on an acceptable candidate before the vote is taken.

He won last month's coalition ballot by one vote over Adel Abdul Mehdi, from the Supreme Council for the Islamic Revolution in Iraq, and was pushed over the top by support from followers of firebrand Shiite cleric Muqtada al-Sadr.

However, opposition to al-Jaafari has been growing, particularly from Kurds and the Sunni-led Iraqi Accord Front, and the Shiite coalition is being pressured to reconsider its decision, Jawad said.

He came under intense criticism as a transitional prime minister for not being a strong enough leader, for not forcing compromise among the various political entities, and for not delivering adequately on the basics -- water and electricity, as well as security.

With many prominent Iraqis recently calling for national unity, even former dictator Hussein said in court Wednesday that all Iraqis should unite against U.S. occupation.

Hussein -- a Sunni Muslim -- reportedly learned of the sectarian fighting during a seven-hour meeting earlier this week with a lawyer. On Tuesday, in Hussein's ancestral homeland of Tikrit, bombers damaged a mosque named for his late father.

About 40 miles (64 kilometers) northeast of Tikrit on Wednesday, insurgents ambushed a convoy of Iraqi police officers, killing four and wounding 11, an Iraqi army officer said.

Maj. Gen. Anwar Mohammed Amin, commander of the army in Kirkuk, said the incident took place during late afternoon on a road between Kirkuk and Tikrit in northern Iraq.

At least 23 people were killed and 58 were wounded, police said, in the midday detonation of a car bomb in the heart of New Baghdad, a mixed neighborhood of Sunnis, Shiites and Christians in eastern Baghdad.

Violence also erupted in Diyala and Babil provinces, northeast and south of Baghdad, two areas where security clampdowns and special curfews were enforced last week as communal vendettas spread across the region.

In Babil province, four mortar rounds Wednesday afternoon struck houses in the al-Askari neighborhood in Mahmoudiya, killing three people and wounding three, police said. Mahmoudiya is nearly 20 miles (32 kilometers) south of Baghdad in the dangerous region known as the "Triangle of Death."

In southwestern Baquba, in Diyala province, gunmen in a car shot and killed three men as they were walking to their carpentry jobs in the al-Gaton neighborhood.

Two people were killed and four were wounded when gunmen attacked a barber shop in Muqdadiya, about 30 miles (48 kilometers) northeast of Baquba in Diyala province, the coalition press office in Diyala said.

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