The Islamic State's gains in the Iraqi city of Ramadi are setback for Iraqi security forces, the top U.S. military ******r said on Monday, adding such setbacks were "regrettable but **t uncommon in warfare." "Much effort will **w be required to reclaim the city," Army General Martin Dempsey, chairman of the U.S. military's Joint Chiefs of Staff, said in a statement. "We will continue to support Iraq's security forces with U.S. air strikes, training, and equipment.