Iraqi forces set oil installations in southern Kuwait ablaze, which could hamper the effectiveness of high-tech allied weaponry, military officials said. The Iraqis also lobbed Scud missiles into Saudi Arabia Tuesday, but their effort was rated as "a big zero."

Warning sirens went off in Dhahran and witnesses reported hearing what sounded like Patriot air defense missiles racing upward to meet incoming Scuds.At a press briefing at the Central Command in Riyadh, Lt. Col. Greg Pepin said military leaders were "encouraged because of the air strikes that have gone in. I'm encouraged because of the disruption in command and control. I'm encouraged that we are hurting Sadddam Hussein across the board in the type of targets we're hitting and I think the campaign is going as planned."

At the al-Wafra oil field in southern Kuwait, oil installations were reported set ablaze by Iraqi forces. The plume of smoke could reduce the effectiveness of weaponry guided with television cameras and lasers and might affect infrared scanners that pilots and weapons officers use to direct their "smart bombs" to their targets.

Air Force 1st Lt. Casey Mahon, a spokesman for the U.S. military command in the Saudi capital, Riyadh, said aerial photography showed oil wells and storage tanks had been blown up at the al-Wafra facility in southern Kuwait, just across the Saudi border.

"We do have evidence that Iraq is damaging or destroying some of these facilities," he said.

Pepin also said oil storage tanks were on fire at a pair of major facilities, Shuaiba and Mina Abdullah, next to each other about 60 miles north of the border.

The official Iranian news agency, meanwhile, reported Tuesday that allied warplanes staged heavy air attacks Monday night and Tuesday on the strategic Iraqi city of Basra, site of Iraq's military headquarters governing operations in Kuwait.

The allied air strikes against Iraq - 10,000 combat and support sorties so far - are only the first stage of a battle that could lead to a bloody ground war. U.S. officials have said that Iraq's military machine is far from broken.

A low-hanging cloud cover over Iraq has hampered the allied air attacks, and the Pentagon also says Iraq has been using wooden decoys to foil attacks on modified Scud missile launchers, a prime target.

In the air campaign so far, 18 allied warplanes have been lost, including nine U.S. aircraft but none in the past day. Twenty-four allied fliers are missing in action, including 13 Americans, the Pentagon says.

Allied warplanes are still seeking to destroy Scud launchers, and Saudi Col. Ahmed Al-Robayan declared, "Iraq has thus far scored a big zero in any effective use of its Scud missiles."

Additionally, four Navy A-6 Intruders attacked an Iraqi vessel and left it sinking, and later Navy fliers hit three other Iraqi boats, sinking one and sending the other two scurrying away. Three more mines were reported destroyed and officials said the mine situation is better now thanit was before the war began.

In the early morning, six Scuds were launched at Riyadh and Dhahran. All were either intercepted and destroyed or hit harmlessly in unpopulated areas. What looked like a nearly intact Scud fell on a street roughly a quarter mile from the hotel where press briefings are given in Riyadh, and Pepin implied it was the carcas of an intercepted missile.

Pepin said Scuds that Patriot radar computers show are not going to hit in populated areas or near military targets automatically tell the Patriot system not to fire an intercepting missile, saving the round for another time when a more threatening launch is detected.

How Iraq views the war

Iraq said Tuesday it had captured another allied airman and that its gunners had shot down 18 allied warplanes and missiles during heavy overnight bombing raids in northern and southern Iraq. An earlier radio report, monitored in Cairo, said Iraqi gunners had shot down four more planes and nine missiles.

Baghdad radio did not mention Iraqi Scud missile attacks on Saudi Arabia, which hosts Islam's two holiest shrines.

Iraq said two Iraqi citizens captured an allied pilot early Tuesday after his plane was shot down but gave no details of the pilot's nationality.

Navy Rear Adm. Conrad Lautenbacker noted that there are 17,000 Marines afloat in the region able to launch amphibious assaults on Kuwait "if needed."

`This is not a video game'

And he played tapes for reporters of a bombing run - showing the view an A-6 Intruder weapons officer sees in trying to put a guided bomb on target - and said it was intended "to show this is not a video game. It is not as simple as putting a cross on a target and flying off."

The raid on a target he would not identify was flown into solid anti-aircraft fire and Lautenbacker said, "This is a deadly serious game," noting that the crew were "able to maintain their cool . . . despite intense anti-aircraft fire."

The cool, steady conversation of the pilot and weapons officer could be heard on the tape saying "impact point is steady . . . 15 seconds . . . impact point is steady . . . stand by for designate." At the explosion of the laser-guided bomb the tape added, "Start the turn . . . round to 230 (a southwest heading) . . . they're shooting at us . . . it's falling away behind us . . . guns are going off all over the place." Flashes of anti-aircraft fire bloomed on the monitor.

Iraqis glad to be rescued

In other developments, the prisoners of war taken off Kuwaiti oil platforms and from a raft in the Persian gulf, officials said, seemed to have been left poorly provisioned.

"I don't think that they wanted to fight," said Cmdr. Dennis Morral, commander of the USS Nicholas, which helped lead the charge. "I don't think they know how to fight. I think they were relieved that we were rescuing them from this situation."

He said the men had no clean clothes for weeks, and appeared to have fished for their meals by tossing hand grenades into the water.

The commander said when U.S. forces captured them, "Most of them put their hands up, thanked us."

In fact, he said, one prisoner "tried to kiss" one of his Navy captors. The U.S. military man declined.