The U.S.-led military coalition says an Afghan working on an installation shared by Afghan and foreign forces has shot and killed three NATO service members. The incident occurred on Friday, raising to six the number of U.S. and NATO troops killed in such attacks on that single day. An Afghan police officer shot and killed three U.S. Marines after sharing a meal with them before dawn Friday in Sangin district of Helmand province, according to a report of the Associated Press. Coalition spokeswoman Maj. Lori Hodge said Saturday that three other foreign soldiers were gunned down Friday night. Their nationalities have not yet been disclosed. She says the shooters in both attacks have been detained. Daud Ahmadi, who is a spokesman for Helmand province, says the second incident occurred in Garmser district.