By Stephen Kalin FALLUJA, Iraq (Reuters) - A highway overpass in central Falluja, from which Islamic State militants hanged a captured Iraqi soldier last year, bears the marks of the city's latest victors, including a slogan scrawled in green spray paint: "The state of (Imam) Hussein remains." The overtly Shi'ite Muslim phrase, which appears to mimic Islamic State's own "Remain and Extend" motto, was left a week ago by one of the Shi'ite militiamen who helped drive Islamic State from the Sunni city it captured in January 2014. With combat over, the militias are staying on, brushing up against army, police and counter-terrorism forces which have each staked out positions across Falluja, heavily damaged by the fighting and now almost completely empty.
