BAGHDAD, Iraq – Insurgents kidnapped a Catholic archbishop and targeted security forces in a series of brazen assaults yesterday that killed more than 20 people. A suicide bomber attacked American Marines in Ramadi, where insurgents also beheaded two Shiite Muslims and left their bodies on a sidewalk.

The top American general in Iraq predicted violence during the January 30 national election but pledged to do “everything in our power” to ensure safety of voters. As part of a crackdown on insurgents, American troops arrested more than 100 suspects over the past three days, American officials said.

In Mosul, Archbishop Basile Georges Casmoussa, 66, of the Syrian Catholic Church, was seized by gunmen while walking in front of his church, a priest said on condition of anonymity. No group claimed responsibility, but the Vatican condemned the abduction as a “terrorist act.”

Christians make up just 3% of Iraq’s 26 million people. The major Christian groups include Chaldean-Assyrians and Armenians with small numbers of Roman Catholics.

The deadliest attacks occurred in three cities in the flashpoint region north and west of Baghdad where Sunni Muslim insurgents are seeking to derail the election.

In Buhriz, 35 miles north of Baghdad, gunmen attacked an Iraqi National Guard checkpoint at the provincial broadcasting center, killing eight soldiers and wounding four. A suicide driver set off a car bomb at a police station in Beiji, 155 miles north of the capital, killing seven policemen and wounding 25 people.

An American spokesman said Marines suffered an undisclosed number of casualties in a suicide car bombing in Ramadi, 70 miles west of Baghdad. Marines sent to check a suspicious vehicle came under small arms and rocket-propelled grenade fire and the vehicle exploded.

“There were U.S. casualties,” Lieutenant Lyle Gilbert said. He declined to give further details, citing security. Later, the American command reported two Marines were killed in action in the province that includes Ramadi, but would not say whether they died in the car bombing.

Elsewhere in Ramadi, a predominantly Sunni Muslim city, officials found the bodies of five civilians and one Iraqi soldier. Each had a handwritten note declaring them collaborators, officials said. Four found together had been shot while two discovered later in the day were beheaded, their blood soaked bodies left where they died. The notes identified the two beheaded victims as Shiite Muslims.

Shiites have been targets of intimidation because they are expected to turn out in large numbers for the election for a 275-member National Assembly that will appoint a new government and draft a permanent constitution.

About 60% of Iraq’s 26 million people are Shiites, and their candidates are expected to win most of the assembly seats. Many Sunni Arabs fear losing the power they enjoyed under Saddam Hussein, and Sunni clerics have called for a boycott of the vote. American officials fear a low Sunni turnout may cast doubt on the legitimacy of the new government.

Yesterday, police discovered a car loaded with explosives in the Shiite holy city of Karbala.

Four mortar shells on Sunday hit schools designated as polling stations in Basra, a largely Shiite city in the far south. An Al Qaeda-linked group led by Jordanian terrorist Abu Musab al-Zarqawi claimed responsibility for the attacks in a statement found yesterday on a Web site, although its authenticity could not verified.

In a statement yesterday, General George Casey Jr., commander of the multinational force in Iraq, said about 300,000 soldiers and police from American, Iraqi, and other foreign forces will be available to protect voters January 30.

“Is there going to be violence on election day? There is, but it’s important that we understand what’s happening here,” General Casey said. “It’s not just about violence. It’s about former regime loyalists and foreign terrorists murdering innocent Iraqis and Iraqi security forces to stop them from exercising their right to vote.”