FALLUJA, Iraq (Reuters) - The U.S. military said on Thursday they had attacked a safehouse belonging to Abu Musab al-Zarqawi, the Jordanian militant Washington says is allied to Osama bin Laden (news - web sites) and al Qaeda. It said the attack took place in a suburb of the restive city of Falluja, but gave no further details, although witnesses said four people were killed when a house in the city was hit by a missile fired from a U.S. warplane. "On June the 30th, multinational forces conducted another strike on a known Zarqawi network safehouse in southwest Falluja based...