U.S. warplanes firing laser-guided missiles destroyed a two-story building in the Iraqi city of Basra Friday, killing some 200 Iraqi paramilitary fighters, the U.S. military said.

The attack targeted the Saddam Hussein loyalists who British officials say have clamped down on a restive population in Basra.

Earlier Friday, the paramilitaries -- known as "Saddam's Fedayeen" -- had fired mortars and machine guns on about 1,000 Iraqi civilians trying to leave the southern city, British military officials and witnesses said.

British forces surround the city -- Iraq's second-largest, with a population of 1.3 million -- and want to open the way for badly needed humanitarian aid. But they have yet to move in, facing what would likely by tough street-by-street resistance from the militiamen.

Friday night's airstrike went after what Central Command called "an emerging target." The pair of F-15E Strike Eagles fired laser-guided munitions fitted with delayed fuses -- meaning they penetrated the building before detonating to minimize the external blast effect. The Central Command statement said a church 300 yards from the two-story building was undamaged.

The statement did not say how it was known that 200 paramilitaries were holding a meeting.

Significant numbers of civilians have reportedly been coming out of Basra every day for the past few days to get food aid from points outside the city and then returning, a senior British defense official said.

That scenario appeared to have happened again Friday, but Iraqi paramilitary forces opened fire on people to block them from leaving, the official said on condition of anonymity.

Britain's 7th Armored Brigade apparently tried to fire back, but stopped out of fear that civilians would be wounded, said Lt. Cmdr. Emma Thomas, a spokeswoman for British forces in the Persian Gulf. As a result, the civilians retreated into Basra in trucks, she said.

An initial group of about 1,000 people made it out safely, fleeing to the west of Basra, and they were being cared for by British forces, who gave them food, water and medical attention, Thomas said.

She said the firing started when a second group of about the same size tried to flee the city.

"Here perhaps are the first pieces of evidence of Iraqi people trying to break free from the Baath party regime and the militia," Col. Chris Vernon, a British military spokesman in southern Iraq, told Sky News Television. "And clearly the militia don't want that. They want to keep their population in there, and they fired on them to force them back in."

British pool reports described Iraqi forces with mortars mounted in pickup trucks firing on the fleeing civilians, sending some running back into Basra. Panicked women and children scattered on a bridge over a canal and down its embankments to avoid machine-gun fire, the reports said.

One Iraqi woman badly wounded by shrapnel was carried into a British vehicle that whisked her off for treatment.

"The local regime in the city is still using fear as its principal instrument to keep the population in line," said one British commander, Maj. Lindsay MacDuff, in a pool report.

"We stopped one guy at a roadblock the other day who told us if we didn't let him escape to the south, either he or his family would be killed. We had to turn him back for security and safety reasons. The next time we spotted him, he was carrying a Kalashnikov in the opposition front line," MacDuff said.

"We can only hope the message gets through that we are here to offer them a lifeline."

On at least three separate occasions, British units and coalition aircraft have fired on Iraqi tanks and other armored vehicles that have streamed out of the city. At least 14 tanks heading south out of Basra were destroyed Thursday, British officials said.

Air Marshal Brian Burridge, the top British commander in the Gulf, said Saddam's paramilitary forces in Basra were forcing regular army troops to fight, threatening to kill them or to harm their families.

The British also say they are coming to the defense of Shiite Muslims who they say rose up in the streets against Saddam's Sunni Muslim regime on Tuesday. Iraq has denied there was an uprising.