The US-led coalition said however its soldiers had come under fire first while trying to conduct a raid against a suspected Taliban safe house in the eastern province of Nangarhar.

The deaths come amid mounting anger among Afghans about the number of civilians killed in military operations against the Taliban, which has stepped up an al-Qaeda-backed campaign against the government and its allies.

The gunfight erupted at midnight Monday and the US troops called in air power, Afghan officials said.

"As the result of a misunderstanding, the coalition forces attacked a police post in Nangarhar province in which seven police were martyred and another five were wounded," interior ministry spokesman Zemarai Bashary said.

"It is not clear what the coalition forces were attacking, if they confused the police post with Taliban or what," he told AFP in the capital Kabul.

The ministry sent a delegation to investigate, Bashary said.

A provincial police commander expressed angry about the deadly incident in Khogyani district, about 30km southwest of the provincial capital Jalalabad.

"They attacked us from ground and air," said provincial police official Nasir Ahmad Safi, identifying the soldiers as Americans.

"They killed seven police brutally," he said, alleging the bodies of the dead each had around 20 bullet wounds. "Unless the criminals are prosecuted, we will not bury the bodies in a protest."

The US-led coalition force said the troops had themselves come under attack while trying to conduct an operation on a "suspected Taliban safe house."

"En route to the location the forces were suddenly ambushed from both sides with rocket-propelled grenades and small arms and returned fire and called in air support and broke contact," spokesman Major Chris Belcher said.

"Following the engagement, the identity of the assailants was called into question. Further details will be released as they become available," he said.

Nangarhar province is on one of the main routes into Afghanistan from Pakistan, where Taliban militants and their allies are said to be trained and armed.

US-led troops and Afghan highway police backed by foreign war planes have killed more than two dozen "enemy fighters" in battles in southern Afghanistan, the US military said yesterday.

The fighting erupted Monday when the security forces were ambushed with rocket-propelled grenades and machine gun fire in the southern province of Kandahar, the US-led coalition said.

They returned fire and "enemy forces retreated after several of their fighters were killed in the brief firefight," it said in a statement.

About five hours later, more than 30 rebels attempted to ambush the same patrol. The security forces "isolated the attackers and then requested close air support to destroy one enemy compound and one enemy vehicle."

"During the eight-hour battle, over two dozen enemy fighters were killed," it said.

The fighting was in the Shah Wali Kot district, the scene of several clashes in recent weeks.

The coalition, focussed on counterterrorism operations, regularly raids suspected militant compounds in the area and has often been accused by locals of killing civilians instead of militants.

It was also in this province that US Marines were accused of opening fire on civilians after a suicide attack in early March. Nineteen civilians were killed, the US military said.

The Nato-led force that operates alongside the coalition said late Monday that its troops had opened fire on a vehicle that did not halt at a checkpoint in eastern Kunar province, killing three Afghan men.

Residents told AFP the casualties were school students aged 14 to 16. Three young men were also wounded, they said.

Nato's International Security Assistance Force announced meanwhile that one of its soldiers was killed and two wounded in an explosion in southern Afghanistan on Monday.

Canada's defence ministry said the casualties were Canadians.

This takes to 81 the number of foreign soldiers killed in Afghanistan this year, most of them in hostile action.

There are around 50,000 foreign troops working alongside the Afghan army and police to defeat an insurgency by the ultra-conservative Taliban that was removed from government in late 2001.