NATO troop deaths

"Five International Security Assistance Force service members died in southern Afghanistan yesterday," NATO said in a statement on Tuesday.

The statement, however, gave no reason for the deaths and did not reveal the soldiers' nationalities. "It is ISAF policy to defer casualty identification procedures to the relevant national authorities," it said.

The force said it was investigating the deaths.

Friendly fire claims

Afghan police said NATO aircraft had bombed the soldiers. One Afghan soldier also died in the incident.

"They were returning from an operation launched in Gazak area of Arghandab district last night and faced a Taliban ambush," said Zabul provincial police chief Ghulam Sakhi Roghlewanay. "They asked for an air support, but the aircraft mistakenly bombed their own soldiers in which five foreign and one Afghan soldier were killed."

The Taliban also said the troops had been killed by friendly fire.

"The enemy soldiers came under mujahideen attack last night in Arghandab district of Zabul province. Their planes came to help them but bombed their colleagues," said Taliban spokesman Qari Yousuf Ahmadi.

NATO withdrawal

The news marks the worst single incident for NATO troops since five British soldiers were killed in a helicopter crash in the southern province of Kandahar on April 26.

The US-led force is winding down operations in Afghanistan, with the remaining 50,000 NATO combat troops due to leave the country after more than a decade of fighting Taliban insurgents.

The news also comes days before a run-off vote in a presidential election in the country.

hc/dr (Reuters, AFP, dpa)