Five more troops, including four American soldiers, were killed in separate attacks in the country.

Also on Monday, London announced that 300 British troops had now died in Afghanistan after a soldier died from wounds suffered in an explosion earlier this month in the southern province of Helmand.

Deadliest month

The latest death toll has made June one of the deadliest months for foreign troops in Afghanistan.

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According to James Bays, Al Jazeera's correspondent in Kabul, more than 60 Nato troops have died this month, making it the deadliest June in the last nine-and-a-half years since international forces have been in the country.

"In fact every single month this year has had a higher death toll than last year - and last year saw more international troops die than any other year in Afghanistan," he said.

The deadliest month for the Western coalition was August last year, when 77 foreign soldiers were killed. Last year, 520 Nato troops died - their deadliest annual total yet.

Australia is the largest contributor - among non-Nato members - to the Isaf alliance, with 1,550 troops currently deployed in the southern province of Uruzgan.

The latest casualties come at a time when a joint Afghan-Nato military operation aimed at rooting out Taliban fighters from their heartland is set to begin in Kandahar.