The Japanese daily Yomiuri Shimbun says the United States wants North Korea to clarify whether it had transferred nuclear materials to Syria as a condition for lifting the communist country from its list of terrorism-sponsoring nations.

The U.S. government had previously demanded that North Korea disable key nuclear facilities at the Yongbyon nuclear complex and declare how much plutonium it has extracted, as well as its purported uranium enrichment program.

The daily says the removal of North Korea from the U.S. terrorism list will take longer than previously expected since the three U.S. conditions are difficult for North Korea to accept.