Afghan policeman turns gun on Marines, kills 3

An Afghan police officer shot and killed three U.S. Marines after sharing a meal with them before dawn Friday and then fled into the desolate darkness of southern Afghanistan, the third attack on coalition forces by their Afghan counterparts in a week.     

Four other international troops also died Friday, bringing to seven the number killed on the day in the violent south, where insurgents have their strongest roots. Three died in an attack, which is under investigation, and the fourth was killed in a separate attack, NATO said.     

Thirty-one coalition service members have now died this year at the hands of Afghan forces or insurgents disguised in Afghan uniforms, according to NATO  a dramatic rise from previous years.     

The assaults have cast a shadow of fear and mistrust over U.S. efforts to train Afghan soldiers and police more than 10 years after the U.S.-led invasion to topple the Taliban's hardline Islamist regime for sheltering al-Qaida's leadership.

The attacks also raise further doubts about the quality of the Afghan forces taking over in many areas before most international troops leave the country in 2014.   

AP