An Iraqi Scud missile wrecked a building housing U.S. soldiers Monday night, setting off a huge fire, eyewitnesses said.

U.S. military police at the scene said they believed there were several dead. More than 20 people were seen being carried away in ambulances. Broadcast reports said at least 12 people were killed in the explosion.The police said there were more than 100 U.S. military personnel in the building when the missile hit at about 8:40 p.m.

"There was a huge explosion, then flames shot into the air," said Greg Seigle, a freelance journalist at the site near Dhahran, near the eastern coast of Saudi Arabia, 200 miles south of Kuwait.

At the Pentagon, a senior military source confirmed "a missile has landed at a military barracks in Dhahran." The official said he couldn't confirm the type of missile or "whose it is."

Seigle said the building "lit up like a Roman candle" after taking a direct hit by a Scud missile.

Air raid sirens sounded in Dhahran at 8:40 p.m. (12:40 p.m. EST), and seconds later the sonic boom of a Patriot missile launch was heard, witnesses said. A smaller explosion was heard seconds later.

During the Persian Gulf war Iraq has repeatedly fired Scud missiles at Dhahran and Riyadh, the Saudi capital to the south. Most have been intercepted by U.S.-supplied Patriot missiles.

Previous Scud attacks on Saudi Arabia killed one person and injured about 85.

Iraq has repeatedly attacked Israel with Scud missiles during the war, killing two people and injuring more than 230.

Three Scuds were fired Sunday night - two at Israel and one at Saudi Arabia.