Angry villagers dug graves Tuesday to bury dozens of suspected militants and civilians killed in one of the deadliest U.S. airstrikes since the American-led invasion in 2001. Another 19 people were killed in new violence.

Taliban fighters ambushed a police patrol in southern Afghanistan, killing three police but leaving 12 militants dead, officials said. Also Tuesday, three health workers and their driver were killed by a land mine near the capital.

The deaths brought to 305 the number of people killed in fighting during the last week. Most of the dead were militants. It's the deadliest spate of fighting in four years and comes ahead of preparations for the U.S.-led coalition to hand over security operations in southern Afghanistan to NATO by July.

CountryWatch: Afghanistan

The coalition said 20 Taliban were confirmed killed in the airstrike on the village of Azizi in Kandahar province late Sunday or early Monday, while up to 60 more may have died.

Local officials said 17 civilians also were killed, but one villager, Haji Ikhlaf, told The Associated Press that 26 civilians had been buried by early Tuesday.

"We've buried women. We've buried children," Ikhlaf, 40, said by cell phone from the area, which has been closed off to reporters by local security forces. "They are killing us. We are so angry."

Villagers also dug graves of slain Taliban rebels, he said.

U.S. commander Lt. Gen. Karl W. Eikenberry told The Associated Press on Monday that the military was "looking into" reports of civilian deaths. Other coalition officials said they were confident they had hit a Taliban compound.

Tuesday's ambush against police occurred in Helmand, a province neighboring Kandahar and heartland of the country's multibillion dollar heroin trade.

Ghulam Muhiddin, the provincial administrator, said dozens of Taliban fled after the attack, leaving the bodies of 12 fighters behind. Police reinforcements were rushed to the area and also found several assault rifles, machine guns and rocket launchers.

The medical workers were killed Monday about 25 miles west of Kabul on a busy road often frequented by foreigners, said Bashar Gul, a local deputy police chief.

The blast killed a doctor, two nurses and their driver, he said. The four worked for the local Afghan Health Development Services.

Militants have repeatedly targeted aid workers, including doctors and teachers. Last month, gunmen stormed a medical clinic in a northwestern province and killed five doctors and nurses.

The Taliban opposes the presence of the development workers because they believe they bolster the U.S.-backed government of President Hamid Karzai.

Militant supporters of the former regime have stepped up attacks this year, drawing a tough response from coalition and Afghan government forces.

The coalition airstrike on Azizi was the third clash there in a week. U.S. Air Force A-10 Warthog warplanes bombed an Islamic school, or madrassa, where the militants were suspected of hiding, before hitting surrounding homes as the insurgents took shelter.

Up to 27 militants were killed in a ground battle and airstrike in the same area Thursday.