BAGHDAD, Iraq – Bombings and shootings killed more than 70 people in Iraq on Tuesday in a surge of bloodshed as U.S. forces prepare to take back Baghdad’s streets from gunmen. The dead included 20 Iraqi troops, a U.S. soldier and a British soldier.

The American soldier, who was assigned to the First Armored Division, died “due to enemy action” in Anbar province west of Baghdad, the U.S. command said. In a separate statement, the military said a U.S. soldier from the 16th Corps Support Group died the day before in a roadside bombing south of the capital.

In further violence, officials confirmed that about 45 Shiite Muslims were kidnapped over the last two weeks on the main highway to Syria and Jordan. The highway passes through Sunni insurgent strongholds west of Baghdad.

The deadliest attack Tuesday occurred when a roadside bomb devastated a bus packed with Iraqi soldiers near Beiji, 155 miles north of Baghdad. All 24 people aboard were killed, Defense Ministry spokesman Mohammed al-Askari said. All but four of the dead were Iraqi soldiers, police said.

In Baghdad, 14 people died and 37 were wounded when a car bomb exploded at a bank where police and soldiers were picking up monthly paychecks, police Lt. Col. Abbas Mohammed Salman said.

It was the third major attack in less than a week in Karradah, a fashionable, mostly Shiite neighborhood in central Baghdad that is home to several prominent politicians. Last Thursday, 31 people were killed in an attack that included rockets, mortars and a car bomb.

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.

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 – like two or three people snatched per day.”

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.