A former top U.S. diplomat says Washington removed North Korea from its terrorism blacklist in 2008 as part of a deal to get Pyongyang to clearly commit to denuclearization efforts.

Japan’s Yomiuri Shimbun said Wednesday that former Assistant Secretary of State Christopher Hill made the statement on Monday during a news conference at the University of Denver, where he serves as dean of the university's Josef Korbel School of International Studies.

Hill also said that the reason Pyongyang agreed to implement early stages of denuclearization during six-way nuclear talks in February 2007 was because the U.S. had promised to ease financial sanctions on the communist state, including resolving the issue of frozen North Korean bank accounts at the Macao-based Banco Delta Asia.