Members of the U.S. Army's vaunted 4th Infantry Division engaged in combat Wednesday for the first time since the Vietnam War, fighting Iraqi paramilitaries and armed men in civilian clothes near an airfield north of the capital.

Additional support — about 20 tanks and 35 Bradley fighting vehicles — was en route to the airstrip after the Iraqis began shooting at Americans clearing the field.

No American casualties were reported in the skirmishes.

"Mostly we're just destroying their equipment as we secure the airfield," said Col. Don Campbell, commander of the 4th Infantry's 1st Brigade.

As of midday, he said, U.S. forces had destroyed a truck, three anti-aircraft guns and two surface-to-air missile systems near the airfield.

"We've encountered six to eight paramilitaries, but we think there will be more when we get to the airfield," Campbell said.

The fighting came after elements of the 4th pushed through Baghdad overnight and set up near the airfield after 40 straight hours on the road from southern Iraq.

The 4th Infantry is considered the Army's most lethal heavy division, boasting the latest tanks, Bradleys and Apache attack helicopters, along with a sophisticated computer system linking all vehicles. But it has missed out on nearly all the fighting in Iraq.

The division originally was supposed to invade Iraq from the north through Turkey. But the Turkish Parliament refused to let the United States use Turkey as a staging ground.

Instead, the division's 14,000 pieces of equipment and 30,000 troops were shipped to Kuwait. They arrived too late to be part of the initial attack.

The 4th Infantry is based in Fort Hood, Texas.