NATO says roadside bombs have killed three of its service members in Afghanistan.

The soldiers were killed Thursday in two separate attacks in the south. The coalition did not give details.

More than 390 international troops have been killed in Afghanistan so far this year.

Taliban insurgents are increasingly using improvised explosive devices to target both security forces and Afghan civilians.

In a report last month, the United Nations said the number of deaths from roadside bombs increased by 17 percent this year compared to the same period in 2010, making them the single-largest killer of civilians in the first half of this year.