KABUL - A soldier from the NATO-led force was killed Sunday and another was injured in a roadside bomb blast in southern Afghanistan, the alliance said. The death brought to 28 the number of NATO-led troops killed this year in violence-plagued southern Afghanistan, said a NATO military spokeswoman, Lieutenant Colonel Maria Carl said.She did not reveal the location or the nationality of the casualties. “There was an improvised explosive device (IED) explosion this morning, killing one (NATO) soldier and injuring another one,” she told a news briefing in Kabul.