Militants tried to blast their way into an American base in eastern Afghanistan on Saturday, striking before dawn with rocket-propelled grenades and a vehicle packed with explosives.

The attackers failed to breach the gate of the base in Panjshir province's Rakha district, though they did hit a security tower with a rocket-propelled grenade, said provincial Police Chief Gen. Mohammad Qasim Jangalbagh.

Three of the men attacked on foot, shooting, while a fourth detonated the explosives-laden vehicle outside the gate, Jangalbagh said. All four of the attackers were killed and two Afghan security guards were wounded, he said.

A NATO spokeswoman confirmed the attack but said there were no American deaths or injuries and no significant damage to facilities.

"There was a complex attack attempted, but it was repelled," Capt. Ebony Calhoun said. She said the guards' wounds were not life-threatening but they had been evacuated to a larger U.S. base for treatment.

NATO spokesmen did not have any immediate details on the attack.

Jangalbagh said there was some damage to the base, but it was unclear how much. The base houses a provincial reconstruction team -- a mix of military and international civilians who work to improve provincial governance, services and infrastructure.

The Taliban claimed responsibility for the attack in a text message sent to The Associated Press.

The attack in Panjshir comes a day after a suicide bombing in southern Afghanistan that killed three Afghan border police officers and one civilian. The bomber blew up his explosives-packed car Friday afternoon while it was being inspected at a checkpoint.

The explosion happened in Spin Boldak, near the Pakistani border, in the early evening, said Gen. Abdul Raziq, the head of the border police in the south.

The checkpoint had been set up because of an intelligence warning that an attack was imminent, provincial government spokesman Zalmai Ayubi said.

Three NATO service members were also killed Friday in separate attacks, according to statements from the military coalition, making 11 killed so far this month and at least 464 since the beginning of the year.