The United States has decided against re－listing North Korea as a state sponsor of terrorism. There had been some speculation Washington might put North Korea back on the list following its alleged hacking attack on Sony Pictures late last year. But the U.S. State Department says Pyongyang is not known to have sponsored any terrorist acts since the bombing of a Korean Airlines flight in 1987. North Korea was removed from the list in 2008 by then U.S. President George W. Bush. The four nations currently listed as state sponsors of terrorism by the U.S. are Cuba，Iran，Syria and Sudan.