The airport is a key first objective for infantry and Marines converging on the capital. Securing it would allow coalition forces to bring in more troops, military equipment and humanitarian aid. 

"We basically occupied the airport," said Lt. Col. Scott Rutter, commander of the 1st Brigade's 2nd Battalion, 7th Infantry Regiment. "Hopefully this is a sign that we're able to send to the residents of Baghdad that we're here and they can rise up and deal with the regime appropriately and save some future battle inside the city." 

Gen. Richard Myers, chairman of the Joint Chiefs of Staff, suggested the airport was not completely under U.S. control. He said it had seemed as if U.S. forces had taken the airport, "and then it got more confusing" with continued fighting. 

Meanwhile, the U.S. Marines 1st Division was massed on the southeastern outskirts of Baghdad on Friday morning after hours of pushing up the Tigris River, past abandoned Iraqi positions, with little resistance. 

However, an Iraqi force was believed standing between them and the capital. Despite highs forecast in the 90s, the Marines pulled on stifling protection suits in case of chemical attack. Some sat alone, lost in their thoughts, while others wrote letters. Some caught a nap after the night's hard drive north. 

During the push north Thursday, Marines fought in close combat in Kut, at one point mowing down a group of Iraqis who mounted a suicide charge against a tank with their AK-47s. The Marines estimated 80 Iraqis died in the fighting at Kut. 

The military said two Marines were killed and one wounded in the close-quarters fighting in Kut. Another Marine was killed near Kut when his automatic weapon went off while he was sleeping, firing one round into his chest. 

Reporters with Marine units moving toward Baghdad said about 2,500 young Iraqi men had surrendered to the Marines overnight. One Marine group had to pause to set up a makeshift prisoner of war camp. 

On the 3rd Division's way to the airport, the troops had to run a gantlet - a single-lane road with Iraqi fighters firing from all sides. For four hours in punishing heat, tanks and Bradley armored vehicles tried to pick out soldiers and fighters amid civilians standing next to houses, watching the armored column pass. 

"Fire, fire, kill them," Capt. Chris Carter of Watkinsville, Ga., the commanding officer of Alpha Company, ordered at one point. 

Staff Sgt. Bryce Ivings of Sarasota, Fla., spotted a fighter and said: "He's got a weapon. Oh ... there's civilians in the way, he's using these people as shields." 

He did not fire. 

At least one U.S. soldier was killed by friendly fire. He was outside his vehicle when U.S. forces blasted an Iraqi tank nearby. Three were wounded by Iraqi fire, and three soldiers collapsed from heat exhaustion as the temperature rose to about 90 degrees outdoors and over 100 degrees inside the tanks and Bradleys. 

One U.S. soldier was shot in the leg as he stepped from his refueling vehicle along the route. He was pulled to safety by comrades who jumped out of a Bradley. 

Along the road from the Euphrates River to Baghdad were hundreds of burning vehicles, civilian and military. Hundreds of dead Iraqis, most in uniform, lay next to the vehicles. 

On Friday, members of the 3rd Infantry continued a sweep through the outskirts of Baghdad amid palm groves, rice paddies, cornfields and irrigation canals, and came across what appeared to be the front line of a Republican Guard company. 

A firefight broke out over a vegetable patch, lasting only about 30 seconds and consisting of only two or three cannon shots. 

Two Republican Guards in uniform were wounded. Two Republican Guards who had put on civilian clothes were also taken prisoner. One, speaking through an interpreter said: "We got bombed last night, and most of our tanks were destroyed." 

Near Numaniyah, southeast of Baghdad, Marines manned a checkpoint Friday on a highway leading to the capital and said they were seeing a steady flow of young men they suspected were Iraqi soldiers trying to rejoin their shattered units. 

One Marine had his M-16 trained on two nervous-looking young men who sat by the side of the road with their arms around their knees. Beneath their long white Arab robes, they were wearing Iraqi military uniforms. One man had an Iraqi military ID card. They were carrying plastic bags containing military jackets. The two men were to be taken away for questioning.