Four Afghan police have been killed and another four injured by American soldiers in southern Afghan province of Helmand, an Afghan official said Friday.

"Four Afghan police were killed and four injured at about 2 p.m. yesterday when they were driving from Kajaki district to Lashkargah, the provincial capital of Helmand and came under attack by a group of US soldiers," Haji Mohaiuddin, deputy governor of Helmand, told Xinhua.

"The US side said it's just an accident, since the US soldiers were carrying out an operation in that area and attacked the Afghan soldiers by mistake," Mohaiuddin added.

"We have heard about the news, but the investigation is still going on," Cindy Moor, spokeswoman of US-led Coalition forces told Xinhua.

It's not the first time that US soldiers have killed Afghan soldiers accidentally. In May 2003, US Special Force guarding American Embassy in Afghanistan opened fire on Afghan soldiers who were carrying weapons across the street, killing three of them and injuring three others.

As one of the troublesome provinces of the country, Helmand is the place Taliban always launched furious attacks against Afghan and foreign troops. Especially after failing to derail the landmark Sept. 18 parliamentary elections, Taliban intensified the attacks which have deprived lives of many persons.

Afghan and US soldiers at the same time also strengthened the fighting back against Taliban. In a clearance operation carried out by Afghan National Army (ANA) on Sunday night, 31 Taliban militants were killed in the eastern province of Paktia.

After the collapse of Taliban in late 2001, about 18,000 US-led Coalition troops, together with 10,000 NATO-led International Security Assistance Force (ISAF) are stationed in the mountainous country to eliminate the remaining Taliban militants and carry out the peacekeeping operation.

Source: Xinhua