MADAIN, Iraq - Iraqi security forces searched this small farming town today after reports that Sunni militants had kidnapped as many as 100 Shiite residents and were threatening to kill them unless the entire Shiite population left town - a display of sectarian violence brazen even by Iraqi standards.

But by late in the day, officials had produced no hostages and there were growing indications the incident had been grossly exaggerated and was perhaps an outgrowth of a tribal dispute or political maneuvering.

The town of about 1,000 families, evenly divided between Shiites and Sunnis, lies about 13 miles south of the capital in what the U.S. military has called the "Triangle of Death" for the danger awaiting U.S. soldiers in an area that has become a roiling stronghold of the insurgency.

An AP photographer and TV cameraman who were in or near the town said large numbers of Iraqi forces had sealed it off, supported by U.S. forces farther outside Madain.

But inside the cordon, the town was calm. The cameraman, who toured the town Sunday morning, said people were going about their business normally, shops were open and tea houses were full. Residents contacted by telephone also said everything was normal in Madain.

American military officials said they were unaware of any U.S. role in what had been described as a tense sectarian standoff.

On Monday morning, an AP photographer joined Iraqi security forces who searched orchards on the outskirts of the agricultural town and streets in central Madain in vehicles and on foot. No hostages were found, and the forces encountered no resistance, the photographer said.

Elsewhere in Iraq, at least 33 people died over the weekend in insurgent violence, including four U.S. soldiers and a 28-year-old American aid worker identified as Marla Ruzicka, of Lakeport, Calif., the founder of a group that was trying to determine the number of civilian casualties in the country.