A roadside bomb has killed three NATO soldiers in eastern Afghanistan.

NATO said the troops were killed Tuesday. The coalition did not provide any other details or the soldiers' nationalities.

The independent website iCasualties.org, which monitors the number of coalition deaths, says 539 international troops have died so far this year in Afghanistan.

The figure represents a decrease from 2010, when over 700 NATO troops were killed in Afghanistan.

The coalition is in the second phase of handing security over to Afghanistan's army and police in a gradual process due to be completed by the end of 2014.