Baghdad, Iraq ? Iraqi security forces surrounded a central Iraqi village today after Sunni militants took as many as 100 Shiite Muslims hostage and threatened to kill the captives if other Shiites did not leave town. The explosive sectarian standoff played out, as 17 people — including an American soldier — were killed in insurgent attacks elsewhere in Iraq.

Late Saturday, insurgents fired mortar rounds at a U.S. Marine base near Ramadi, 70 miles west of Baghdad, the military said, adding that there were no American casualties. Residents said dozens of armed fighters moved through the city after dark. They reported loud explosions when the militants tried to force their way into Camp Blue Diamond and said there were casualties among the attackers.

In the southeast, 11 Iraqi detainees angry at their treatment by American jailers broke out of Camp Bucca, the American military’s largest detention center, by cutting through a fence. Ten were recaptured, U.S. and Iraqi authorities said.

The Sunni-Shiite conflict exploded Thursday in Madain, 15 miles southeast of Baghdad, when Sunni militants attacked the town mosque with explosives. National Security Minister Qassem Dawoud said government security forces had the town surrounded and were conducting raids to root out the hostage-takers. He said U.S.-led forces were backing the operation, but the U.S. military said it had no information.

Haitham Husseini, a spokesman for the Supreme Council for Islamic Revolution in Iraq, the country’s largest Shiite group, said the Madain mosque had been badly damaged in the Thursday attack.

Husseini said about 100 masked militants drove through Madain, capturing Shiite youngsters and old men. He and government officials said between 35 to 100 people were taken hostage.

A resident reached by telephone said the militants had returned early Saturday, shouting through loudspeakers that all Shiites must leave or the hostages would be killed. Later, the resident said, the town appeared calm and there was no sign of insurgents. Other residents said no hostages had been taken. The conflicting accounts could not be reconciled.

Dawoud told al-Arabia television that insurgents loyal to Jordanian-born militant Abu Musab al-Zarqawi, leader of the feared group al-Qaida in Iraq, were operating throughout the area.