The three died in an improvised explosive device (IED) attack in eastern Afghanistan, it said in a statement, without giving any further details in line with policy.
IEDs are a frequent killer of both troops and civilians in Afghanistan`s Taliban-led insurgency, which has been raging for ten years since a US-led invasion in 2001.
Separately, two other troops died in separate incidents, one due to an insurgent attack in Wardak province, eastern Afghanistan and another "as a result of a non-battle related injury" in southern Afghanistan, ISAF said.
At least 459 international troops have been killed in Afghanistan this year, according to independent website iCasualties.org.
There are 140,000 foreign forces in Afghanistan, some 100,000 of them from the United States.
All combat troops are due to leave by the end of 2014 although thousands are likely to remain in training and mentoring roles.
(Uu.H-AK)
Editor: Priyambodo RH
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