Britain's Defense Secretary Philip Hammond insists troops are committed to their mission in Afghanistan, after the number of U.K. personnel killed there passed 400, according to AP. Ministers fear the deaths of six soldiers after an explosion hit their armored vehicle in the southwestern Helmand province Tuesday evening will prompt new concern over the campaign. The incident was the biggest loss of life for British forces in Afghanistan since a plane crash in 2006. It took Britain's death toll since 2001 to 404. Hammond told ITV television Thursday that morale in Afghanistan "is extremely high" and forces remained committed. But Gen. David Richards, head of Britain's armed forces, acknowledged that "as we hold that course, it is likely that others will lose loved ones."