Iraqi security forces found 53 corpses, blindfolded and handcuffed, in a town south of Baghdad early on Wednesday, local officials said. Sunni Islamist fighters seized control of large parts of **rthern and western Iraq last month, sweeping toward Baghdad in the most serious challenge to the Shi'ite-led government of Prime Minister Nuri al-Maliki since the withdrawal of U.S. forces in 2011. Sunni militants have been carrying out attacks around the southern rim of Baghdad since the spring. In response, Shi'ite militias have been active in the rural districts of Baghdad, abducting Sunnis they suspected of terrorism, many of whom later turn up dead.