By Ghazwan al-Jibouri

BISHKAN, Iraq, July 3 (Reuters) U S troops rounded up 450 men in a village north of Baghdad over the weekend and held them for up to two days, questioning them about the presence of foreign fighters in the area, the mayor said today.

The village of Bishkan is just east of Dhuluiya, where Iraqi officials said last week that 15 foreign fighters were killed in clashes with U.S. and Iraqi forces. A Tunisian al Qaeda militant accused of bombing a revered Shi'ite shrine was wounded.

The U S military confirmed that U S and Iraqi troops had conducted a major operation to capture any militants operating in or around Dhuluiya and to ensure ''the surrounding villages were safe from indiscriminate attacks''.

''Initially, 170 people were questioned based on the various pieces of information. Of the original 170, the Iraqi soldiers have determined only 44 people warranted further investigation,'' U S military spokesman Major Will Willhoite said.

The mayor of Bishkan, Jasim al-Dulaimi, said 450 men were held in the operation, which started early on Saturday. ''All the men of the village were detained,'' he told Reuters.

Villagers said U S troops using loudspeakers had ordered all males above the age of 15 out of their houses and then held them in the local school.

Farmer Awad Mudhir, 40, said he was detained for six hours along with his 12-year-old son, who was freed after an hour.

Awad said: ''They asked us about if we knew any foreign Arab militants who are attacking the Americans. We said we didn't.'' Othman Khidir, 36, a doctoral student in religious studies in Baghdad, said he saw one detainee beaten, but this could not be independently confirmed. Willhoite said the operation was largely conducted by Iraqi forces with U.S. troops in support.

''I also saw five boats blown up,'' he added. The U.S.

military made no reference to the destruction of boats in its statement. Troops have previously destroyed such boats on the Tigris river at Dhuluiya to prevent guerrillas using them.

Saad Saleh, 28, a fisherman who spends his days on the Tigris, said he had been arrested along with four cousins, three of whom were teachers. He had not seen them since his release.

His boat was among those destroyed, he said.

Police said most of the detainees had been freed at 2 a.m.

today (0330 hrs IST), but 36 men had been placed under formal arrest and had not been let go.

Villagers spoke mainly of seeing U S forces involved in the operation, but Willhoite said it had been conducted mainly by Iraqis with U S troops performing ''outer cordon security''.

He said a cache of almost 20 mortar rounds and three sniper rifles had been found.

REUTERS SHR HT1802