Japanese newspapers say the United States and Japan could inspect North Korean vessels in international waters around the Korean Peninsula suspected of carrying nuclear materials.

Deputy U.S. National Security Adviser Jack Crouch briefed Japanese Vice Foreign Minister Shotaro Yachi Thursday on the potential for additional sanctions on North Korea.

The Japanese daily Sankei Shimbun says Washington is expected to seek a U.N. Security Council resolution on examining North Korean ships believed to be loaded with nuclear materials.

Another daily, the Nihon Keizai, says the United States is considering demanding that South Korea and China stop providing energy for and trading with the North.

U.S. Under Secretary of State Nicholas Burns plans to go to Seoul and Beijing to ask for cooperation with the sanctions.