KABUL, Afghanistan, AP – Hundreds of Taliban fighters firing rocket-propelled grenades on Monday attacked a district headquarters in southwestern Afghanistan, killing three police and wounding seven, amid of a flurry of suicide attacks, roadside bombings and shootings that claimed lives across the country.

A car bomb seriously wounded two U.S.-led coalition soldiers near Kandahar, and in another incident, four suspected suicide attackers riding two motorcycles died in a confrontation with Afghan police. In the west, gunmen killed two Afghans working for international aid agency World Vision who had been delivering medicine.

It was the latest in a bloody wave of violence between resurgent Taliban-led rebels and Afghan and foreign troops, and comes as NATO-led forces prepare to take over command of security operations in the hard-line militia’s former southern heartland.

The heaviest fighting took place in Bakwa, a town in southwestern Farah province, which has been spared from the worst of the recent violence that has claimed more than 800 lives, mostly militants, since mid-May.

About 400 Taliban militants riding in about 35 pickup trucks arrived in the town late Sunday and launched a heavy assault on a district police and administration headquarters using dozens of machine guns and rocket-propelled grenade launchers, said Gen. Sayed Aga Saqib, provincial police chief.

The militants fled back toward neighboring Helmand province after a five-hour battle, carrying an unknown number of militant casualties with them from a bloodstained battleground. The clash left three police dead, and seven wounded, he said.

Also in Farah, four suspected suicide attackers riding on two explosive-laden motorbikes were killed after they were challenged by police as they drove through the provincial capital late Sunday, Saqib said.

Two of the suspected attackers were shot dead by police, while the other two were killed when police shot at their bike and detonated their explosives, Saqib said.

A boy passer-by also was killed in the explosion, while the child’s father was wounded, Saqib said.

Meanwhile, a remotely donated car bomb seriously wounded two U.S.-led coalition soldiers Monday as they patrolled with Afghan army soldiers in Daman district of southern Kandahar province, on the main highway toward the capital Kabul.

A van had appeared to have broken down on the road, then exploded as the patrol passed, said coalition spokesman Maj. Scott Lundy.

Afghan officials said it was a suicide attack but the coalition said initial reports showed the bomb was remotely detonated from a house.

The coalition declined to reveal the wounded soldiers nationalities or identities. Lundy said their conditions were “serious but not life-threatening.”

In eastern Afghanistan, an attacker traveling in a taxi from neighboring Pakistan exploded two grenades at a border police checkpoint in Khost province late Sunday, killing a civilian and wounding three others, police said.

The attacker threw the first grenade at police, but failed to hurt anyone. As police surrounded the car, the attacker detonated a second grenade, which killed him and one other person in the car, said Gen. Mohammed Ayub, the regional police chief. Three other passengers were wounded.

In western Ghor province, gunmen killed a doctor and a driver for the aid agency World Vision as they were driving back to Chaghcharan from the town of Charsada, where they had delivered medicine, said Karimuddin Razazada, deputy governor of Ghor province. It wasn’t immediately clear who was responsible for the attack.

Afghanistan is experiencing its worst spate of violence since late 2001, when the Taliban regime was overthrown in a U.S.-led invasion.

The most intense fighting has been in the south, where NATO is bolstering its presence as it prepares to take over the security of the region from U.S.-led coalition by the end of July with troop numbers increased to 16,000 from 9,700.

It’s one of the biggest and most dangerous missions in NATO’s history, and has been met with stiff resistance from Taliban-led fighters who increasingly appear to adopt methods used by militants in Iraq.