2 U.S. troops killed by Afghan partners

? Two U.S. troops were gunned down by two Afghan soldiers and an accomplice Thursday, the latest of six American service members killed by their Afghan partners since the burning of Muslim holy books at a U.S. base last week sent anti-Americanism soaring in a nation that has long distrusted foreigners.

The killings come at a time when international troops have stepped up training and mentoring of Afghan soldiers, police and government workers so the Afghans can take the lead and the foreign forces go home. Success of the partnership, the focus of the U.S.-led coalition’s exit strategy, is threatened by a rising number of Afghan police and soldiers — or militants disguised in their uniforms — who are turning their guns on their foreign allies.

The latest victims were killed on a joint U.S.-Afghan base in Zhari district of southern Kandahar province by two Afghan soldiers and Afghan civilian literacy instructor who fired from a sentry tower, according to U.S. and Afghan officials. NATO forces shot and killed two of the assailants, apparently the soldiers, said Pentagon press secretary George Little.

On Feb. 25, two U.S. military advisers were found dead with shots to the back of the head inside the Afghan Interior Ministry in Kabul. Two U.S. troops were killed Feb. 23 by an Afghan soldier during an anti-Western protest over the Quran burning.

The U.S. apologized for the burning, saying the Islamic texts were mistakenly sent to a garbage burn pit Feb. 20 at Bagram Air Field, north of Kabul.