Updated

U.S. Marines attacked a Taliban convoy near Kandahar for the first time Friday, killing seven fighters in their first offensive ground action since setting up base in southern Afghanistan.

No Marines were injured in the attack, according to Pentagon officials.

Three Taliban vehicles approached a "hunter-killer" team of patrolling Marines on a road Thursday night, and the Marines attacked from the ground and from the air, said Capt. David Romley.

"The enemy were shot dead," Romley said. "The forces killed were believed to be Al Qaeda and Taliban forces."

Some of the Taliban and Al Qaeda forces were in vehicles and some jumped out, fighting from the ground, he said. The Marines on the ground destroyed one of the vehicles, and U.S. aircraft destroyed two more. It was unclear whether the aircraft came from the Marine airstrip or were based at sea.

Romley didn't specify the time of the attack, nor specify where it occurred, other than to say it was on a road "near Kandahar." Kandahar was the last major city under Taliban control, and was being occupied by anti-Taliban Pashtun forces on Friday.

Romley said the attack was the Marines' first offensive ground operation since seizing a desert airstrip as Forward Operating Base Rhino on Nov. 25.

Since the Marines seized the desert airstrip, their only combat operation came on their second day, when Cobra helicopter gunships from the base helped warplanes from elsewhere attack a suspected hostile convoy that passed nearby.

But the Marines had announced Wednesday that they would move to a more aggressive mode to prevent the Taliban from escaping or bringing reinforcements into Kandahar.

The Marines also reported Taliban forces around the base itself, which went on alert Thursday night after lookouts spotted Taliban fighters "probing the perimeter of the base," Romley said.

The Marines shot flares into the night sky, and fired mortars into the desert. An automatic grenade launcher also was used, Romley said.

A UH-1N Huey helicopter also crashed near the airstrip at Camp Rhino on Thursday, but Romley said it did not appear to be due to enemy action. Two servicemen suffered minor injuries, he said.

Smoke billowed over the base, and the fire gave the night sky a red glow.

During the enemy "probing," small arms fire reverberated through the desert base along with the crisp blast of outgoing mortar rounds. Flares lit up the flat, dusty desert around Camp Rhino while journalists crouched in trenches.

Journalists in the camp, who were issued military flak jackets and helmets, could see no incoming fire. However, they heard shouting outside the camp and the sound of gunfire. Helicopters made sweeps overhead in the clear night sky.

Defense Department rules governing the journalists' presence in the camp forbid reporting on exact operational measures. In all, the base went on alert three times overnight.

Marines from Camp Rhino also were called into action on Wednesday after an errant U.S. bomb killed three U.S. servicemen and five anti-Taliban Afghan fighters. Twenty Americans and about 20 Afghans were injured.

Some of them were flown to the base, which has a Navy field medical unit with 10 doctors. The Americans and some of the Afghans were immediately flown out on C130 transports to hospitals elsewhere.

Reporters at the base were kept away from the medical unit as the casualties were brought in.

Maj. James Parrington, executive officer of the Marine Expeditionary Unit 15th's Battalion Landing Team 1, said other troops at the base were aware of the incident and that it has steeled them for the fight.

"This is real. We're not playing around. There are people out there who mean us ill will. It is serious," Parrington said.

The Marines, which U.S. officials have said number about 1,300, include the 15th and the 26th Marine Expeditionary Units, equipped with heavily armored vehicles and anti-tank weapons.

The Associated Press contributed to this report.