The United States left out North Korea from its list of states sponsoring terrorism despite calls for adding Pyongyang to the list in the wake of a massive hacking attack on Sony Pictures late last year.

"The Democratic People's Republic of Korea (DPRK) is not known to have sponsored any terrorist acts since the bombing of a Korean Airlines flight in 1987," the State Department said in Country Reports on Terrorism 2014, referring to the North's official name, Yonhap News Agency reported.

North Korea was put on the US terrorism sponsor list for the 1987 midair bombing of a Korean Air flight that killed all 115 people aboard. But the US administration of former President George W. Bush removed Pyongyang from the list in 2008 in exchange for progress in denuclearization talks.

Calls grew for redesignating Pyongyang as a state terrorism sponsor after the FBI determined the North was responsible for the cyber-attack on Sony Pictures last November, but the State Department was negative about its effectiveness.

The latest report said that the North was removed from the list "in accordance with criteria set forth in US law, including a certification that the DPRK had not provided any support for international terrorism during the preceding six-month period and the provision by the DPRK of assurances that it would not support acts of international terrorism in the future."