In an effort to strike at Iran's influence in the Middle East, US President George W. Bush has authorized US forces in Iraq to apprehend or kill Iranian agents operating in that country, the Washington Post reported Friday. According to the article, the "catch and release" policy on Iranian suspects that the US military has employed in Iraq for over a year was determined by defense officials to be ineffective. "There were no costs for the Iranians," an administration official told the Washington Post. "They are hurting our mission in Iraq, and we were bending over backwards not to fight back." US policy has dictated that suspected Iranian operatives be detained and held for three to four days, during which they would undergo retina scans, fingerprinting, and be photographed for intelligence purposes. Some DNA samples were also collected without the detainees' knowledge, according to the report, which said that these arrests were conducted largely in secret. Intelligence officials said that to date, the US administration has no evidence that Iranian agents have attacked US personnel in Iraq, but added that some 150 Iranian operatives are believed to be working in Iraq. The officials also said that Iran has been planting agents in Iraq as advisors and weapons suppliers to Shi'ite insurgent groups. Currently, US forces are permitted to kill Iranian Revolutionary Guard members identified in Iraq, as well as Iranian intelligence officers who cooperate with Iraqi militias. Iranian civilians and diplomats are not valid targets.