KABUL: Afghan and international authorities said Saturday that more than a dozen insurgents had been killed in new clashes in Taliban and Al-Qaeda hotspots, as a district police chief and his guard died in a bombing.

Authorities were meanwhile following up a major attack on a remote outpost in the east of the country on Friday that killed three US, two Latvian and three Afghan troops in one of the deadliest incidents for the security forces in months.

The US military announced that its forces working with Afghan troops had killed five militants on Friday in the southern province of Helmand, a stronghold of the Al-Qaeda linked Taliban militia.

The troops had come under attack while on a routine security patrol and "returned fire with small-arms and heavy weapons, killing five militants," it said in a statement.

Six to seven more militants were killed overnight in the adjoining province of Kandahar, provincial police intelligence chief Abdullah Khan said.

They had been travelling in a pick-up vehicle and were targeted by an air strike, he said.

The defence ministry said separately that its men had killed one "terrorist" on Friday in the eastern province of Paktika.

None of the incidents or tolls could be independently confirmed.

The interior ministry reported meanwhile that the police chief of Farsi district in the western province of Herat was killed, along with a bodyguard, early Saturday when a bomb blew up their vehicle.

It blamed the attack, in which six policemen were also wounded, on insurgents.

Attacks and clashes linked to a Taliban-led insurgency have picked up in recent weeks and the militants warned days ago that they would launch a new operation against the Afghan forces and the international troops helping them.

In one of the deadliest attacks on the security forces in months, a group of insurgents stormed a small outpost in the remote northeastern province of Kunar around midnight Thursday, with the fighting extending into Friday.

Three US and two Latvian soldiers were killed in the clash, international militaries said.

The Afghan defence ministry said three Afghan soldiers also died in the incident in the Ghaziabad district, near the border with Pakistan.

Several Taliban were also killed and wounded, Afghan officials said, without being able to give a clear number.

"The fight is ongoing," said the district chief, named only Mursalin, adding operations were moving into valleys where the attackers were believed to be based.

"We are still looking for information on who might have caused this," US military spokesman Colonel Greg Julian told AFP.

There were around 30 men at the outpost when it was attacked, he said, adding that they had called in air support.

"There was an ammunition bunker that exploded and may have caused some of the casualties," he said.