Three Americans killed after argument with Afghan soldier - officials

KABUL (Reuters) - Three Americans, two soldiers and a civilian, were killed in Afghanistan on Saturday when a man in an Afghan army uniform turned his weapon on them in the eastern province of Paktika, the NATO-led force said.

So-called insider attacks by Afghan soldiers on their NATO-force allies have become an increasing problem over the past year or so, threatening to undermine already waning support for the war among Western nations sending troops.