NATO troops have killed an Afghan soldier who tried to gun down coalition service members at a military base in eastern Afghanistan.

A NATO spokesman says no coalition troops were killed in the attack Thursday in Laghman province, but declined to say if any were wounded.

The shooting is the second apparent attack by Afghan forces on their foreign counterparts this week. NATO said Tuesday two gunmen wearing Afghan National Army uniforms killed a coalition soldier.

So far this year, there have been at least 25 so-called “green-on-blue” (reference to uniforms) attacks in which foreign troops have been killed by Afghan soldiers or insurgents disguised in their uniforms.

Thursday's attack comes a day after suicide bombers detonated their explosives near a NATO patrol in the capital of Kunar province, killing three coalition soldiers, an Afghan civilian and a USAID Foreign Service officer.

U.S. Secretary of State Hillary Clinton issued a statement Thursday, identifying the officer as Ragaei Abdelfattah and expressing condolences to his family. Clinton said over the last 15 months, Abdelfattah partnered with local officials in eastern Afghanistan to help establish new schools and health clinics, and deliver electricity to the residents of Kunar and Nangarhar province.

A State Department Foreign Service officer was also wounded in Wednesday's suicide blast.