Three NATO soldiers were killed in a bomb attack in eastern Afghanistan.

In a brief statement, the NATO said the troops died on Sunday. The invaders did not provide their nationalities or further details about the bombing.

Most of the troops in eastern Afghanistan are American, but there are also troops in the region from other countries.

In another incident, A U.S. soldiers was killed in southern Afghanistan on Sunday on a patrol with Afghan security forces when one of the Afghans turned his weapon on the Americans, the latest in a rash of what the ISAF is now calling “insider” attacks on American troops.

The incident comes just days after the U.S. military told troops to be constantly armed and ready for attack, both inside and outside their bases. Twenty U.S. troops and one aid worker have been killed in Taliban attacks in the past two weeks, 10 of them shot to death in cold blood by rogue Afghan soldiers or policemen.

The number of “green on blue” attacks this year already exceeds the total for last year. Since the beginning of 2012, there have been 32 attacks resulting in 40 deaths, far more than last year’s 21 total attacks.