Iraq\'s Tikrit City has been put under curfew following clashes between armed militants and policemen at a prison. Armed militants attacked a prison in the Iraqi city of Tikrit, as joint police and army forces were deployed at the prison, Iraqi police sources told KUNA One of the prison guards was killed and three others wounded in the clash, the sources said. But, they failed to reveal whether or not some prisoners managed to escape the prison. Militants have previously targeted Iraqi prisons in similar operations.