On Thursday, militants placed explosives inside a local mosque, severely damaging it, said Haitham Husseini, a spokesman for the Supreme Council of Islamic Revolution, Iraq's largest Shiite group. The following day, they returned and seized between 35 and 50 Shiite men, he said.
"There were about 100 masked men, riding in cars, roaming the city. They took hostages from the Shiite youth and old men, and demanded the Shiites leave the city," Husseini said. "The families contacted us yesterday and they asked for our help ... There is a fear now among the women and children."
Husseini said insurgents who follow the fundamentalist Muslim brand of Sunni Islam called Wahhabism were trying to spark sectarian strife in the town, populated by a near equal mix of Shiites and Sunnis. But he said Shiites would not retaliate.
"Until now, we're not getting involved. We're waiting for the government to do what it has to do," Husseini said.
He said his group had asked the Iraqi interior and defense ministries to take action in the town, about 15 miles southeast of Baghdad.
In other developments in Iraq:
A Defense Ministry official said at least 70 people had been taken hostage in Madain and Iraqi security forces were surrounding the area, trying to contain the situation.
Sabah Khadum, an official at the Interior Ministry, said the militants had come from outside the town and were trying to stir up conflict among its residents.
"They are trying to make use of the multiethnic nature of the city," he said.
Sunni insurgents repeatedly have sparred with Iraq's security forces — which are dominated by Shiites — in Madain and its outlying districts.
In raids two weeks ago, Iraqi soldiers arrested more than 80 insurgents in the nearby Salman Pak area, 20 miles southeast of Baghdad.
Late last month, Iraqi commandos, backed by U.S. air and ground fire, assaulted an insurgent training camp in the region, reportedly killing 85 suspected insurgents.