The British soldier was fatally wounded in a mortar barrage before dawn Tuesday on a British base in the southern city of Basra, the British Defense Ministry said. Britain has lost 115 soldiers in Iraq since the U.S.-led invasion in March 2003.

There was no claim of responsibility for the barrage. But it followed a crackdown by the British on Shiite militias that have infiltrated security forces in the city and threaten the authority of the government in Baghdad.

In the southern city of Najaf, Gov. Assad Abu Kilal said 45 people from his province had disappeared while traveling by bus through the Sunni-dominated area west of Baghdad. He demanded the government stop the kidnappings or he would send his own forces to protect the road.

A senior Interior Ministry official, Saadoun Abu al-Ula, confirmed that more than 45 people from the Najaf area were seized but said "it's been going on for the past two weeks ¡ª like two or three people snatched per day."

Late Tuesday, an Internet statement by the al-Qaida-affiliated Mujahedeen Shura Council claimed "the resistance" captured 37 Najaf policemen Monday near Ramadi as they returned from a training course in Jordan. It was unclear if they were from the group cited by the Najaf governor.

U.S. officials have also grown alarmed over the rise in Sunni-Shiite violence and the role of sectarian militias. Those tensions are now considered a greater threat than the Sunni insurgency to the government of Prime Minister Nouri al-Maliki.

The U.S. military is moving at least 3,700 soldiers from Mosul to Baghdad and is gearing up for a new security operation to wrest control of the capital from Shiite militias, Sunni insurgents, kidnap gangs, rogue police and freelance gunmen.

U.S. officials have described the Baghdad campaign as a "must-win" for al-Maliki, whose government has been unable to curb the rise in violence since it took office May 20. American troops will work alongside U.S.-trained Iraqi forces.

As part of the campaign against militias, U.S. troops on Tuesday arrested a Baghdad-area representative of radical Shiite cleric Muqtada al-Sadr, whose Mahdi Army is among the most feared armed groups.

The arrest of Sheik Ahmed al-Ashmani was reported by al-Sadr's staff, which said 10 other members of the cleric's movement were detained. There was no confirmation from the U.S. military.

Meanwhile, gunmen ambushed a minibus carrying employees of a power station to their homes in the Shiite district of Sadr City, killing five passengers and wounding six, police said.

A car bomb killed seven people, six of them civilians, in Muqdadiyah, about 60 miles northeast of Baghdad and a flashpoint of Sunni-Shiite tensions. Three Iraqi soldiers were killed Tuesday evening when a suicide car bomber attacked a checkpoint in the northern city of Tal Afar, the Iraqi army said.

An Iraqi journalist working for the Iranian government-run Al-Alam television was slain in western Baghdad. Adil al-Mansuri, an Iraqi in his 20s, was stopped by gunmen Monday and shot, according to a colleague, Aysar al-Yasiri.

A Sunni Arab politician, Mohammed Shihab al-Dulaimi, was kidnapped Tuesday in Baghdad, his associates said. Al-Dulaimi is the spokesman for a coalition of political groups that rejected the results of the Dec. 15 parliamentary elections.

The other victims reported by police died in a series of shootings and bombings, mostly in Baghdad.