As dawn breaks over Baghdad, men wearing gloves and heavy boots fan out to collect discarded tires, then set them afire. Other residents search for old clothes, bits of plastic - anything that burns.

It's a strange spectacle, but the aim is simple: to create a thick, black smokescreen that might help shield the capital from allied air strikes.The bonfires are among many low-technology methods used by the war-hardened Iraqis in their effort to offset the far superior military might of the U.S.-led forces.

Housewives separate papers and other flammable materials before throwing the garbage away. Teenagers, unmindful of the air raid sirens, collect old shoes, scraps of plastic and other refuse that will smolder smokily.

The campaign is spearheaded by members of President Saddam Hussein's militia, the Popular Army.

In every corner of this sprawling city of 4 million, residents search for discarded tires. They even remove tires from stranded or broken-down vehicles, which abound because of the lack of spare parts.

The collected tires are set on fire under the bridges over the Tigris River that connect the western and eastern districts of Baghdad.

Tires also are burnt elsewhere in the city, sometimes spewing smoke so thick that the sun is blotted out.

Besides reducing the visibility of allied pilots, the smoke may give a false impression to surveillance satellites that parts of Baghdad are burning.

"We may not be Rambos and we may not have `Star Wars' capabilities, but we know how to defend ourselves," said a member of the Popular Army militia.

The militia is Saddam's second line of defense, trained in civil defense and also in hand-to-hand combat in case the war over Kuwait reaches Baghdad one day.

Bags made of jute, collected by Popular Army soldiers and civilians, are wrapped around the iron railings of the bridges over the Tigris.

Small tree branches and green leaves are then fixed to the bags in an attempt to camouflage the bridges from air attack.

"We know the jute bags and the tree branches may not save the bridges, but at least we are trying to save our city with whatever we have," said an Iraqi civil defense official.

Some car owners try their own hand at camouflage, smearing their vehicles with mud paste.

Four weeks of intense bombing have had an impact on Baghdad's residents, who are less likely now to joke about the U.S. Army or the threat of destruction.

There is, however, no visible sign of panic. Residents disregard the air raid sirens, and even the raids themselves, to go about their business.

In the first two weeks, military targets and communication centers were hit. More recently, the raids have destroyed government and private buildings across the city.

There is tremendous anger directed at the United States and a growing feeling that Saddam should not have invaded Kuwait in the first place.

"We Iraqis were slowly returning to normal life after our war with Iran (from 1980-88). There was no need to invade Kuwait," said an employee at the al-Rashid Hotel who did not want to give his name.

"We don't need the oil," he said. "We need to live."