NICOSIA, CYPRUS, JUNE 22 -- Iranian forces have captured the town of Mawat and 15 villages in northern Iraq and killed or wounded 1,500 Iraqis, Iran's official Islamic Republic News Agency (IRNA) reported today.

The report, monitored here, said the latest fighting brought to 3,500 the number of Iraqi casualties since Saturday.

Meanwhile, Kuwaiti Oil Minister Ali Khalifa Sabah said at a news conference in Kuwait that his country will seek protective flags from the Soviet Union or other nations if Congress blocks President Reagan's plan to fly the U.S. flag on 11 Kuwaiti tankers as a means of protecting them from attack by belligerents in the Iran-Iraq war.

"It is up to Congress and the administration to decide whether it is in the interest of the United States to reflag Kuwaiti tankers," he said. "After giving everybody a chance, we would be satisfied to get our tankers reflagged by the Soviet Union. We will turn to other countries to reflag our ships if Congress denies us this. We have approached three countries -- Britain, France and China." He said the three had not yet responded.

On the battlefield, Iranian troops have been advancing into Iraq's rugged mountain terrain since their latest offensive was launched Saturday night, IRNA said. Iran has captured 24 square miles of Iraqi territory so far, it said.

An Iraqi military spokesman in Baghdad said there was fierce fighting in the area but that the Iranian claims were "much exaggerated."

Mawat is in the Kurdish highlands of northern Iraq, about eight miles from the border, in the area where Iranian-backed Kurdish rebels demanding their own homeland are battling the Iraqi government.

Also today, Iran's main resistance group, the Mujaheddin Khalq, claimed it killed or wounded 41 government troops in an attack on an Iranian military camp Thursday.

The Mujaheddin claim to have killed or wounded 640 Iranian troops in the past two weeks.