Two suicide attackers exploded car bombs in separate assaults on U.S. and Afghan forces Friday, slightly wounding two U.S. military members and one U.S. civilian contractor, officials said.

Both bombings occurred around 11:30 a.m. in the southern province of Helmand, a hub of Afghanistan's drug trade and Taliban rebellion. Both attackers died.

One bomb went off outside the main gate of a so-called provincial reconstruction team base run by British personnel in Laskargah, the main town in Helmand.

The provincial police chief initially reported that a British vehicle was damaged in the attack, but the British Defense Ministry said the bombing happened near a U.S. convoy and no British troops were involved.

A U.S. military statement said the three Americans suffered minor injuries and Afghan police were investigating the attack.

In the province's Sangin district, an attacker tried to detonate a bomb among a convoy of Afghan army trucks, causing minor damage to one vehicle but not harming anyone else, said Ghulam Muihiddin, spokesman for the provincial governor.

Two suspected militants were killed Thursday when a land mine went off in their car in eastern Afghanistan, police said. The blast happened in Yakubi district of Khost province, near where the militants had laid another land mine by a road, said provincial police chief Mohammed Ayub.

Elsewhere in the province, a remote control roadside bomb narrowly missed a district police chief as he passed in a car in Tani district Thursday, but a 13-year- old girl who was gathering firewood nearby suffered shrapnel injuries.

Germany's Defense Ministry reported that four of its soldiers were injured in two separate attacks this week in northern Afghanistan.

One German was wounded in an attack Thursday on a patrol north of Kunduz, ministry spokesman Thomas Raabe said. The remote-controlled explosives attached to a bicycle killed an Afghan civilian and wounded three, he said.

In a separate incident near Faizabad on Wednesday night, three German soldiers suffered slight injuries in an exchange of fire with assailants who apparently used a rocket-propelled grenade and a submachine gun.

Supporters of the former Taliban ruling militia, which was ousted by U.S.-led forces in late 2001, have stepped up resistance to foreign troops and the government of President Hamid Karzai.