Japan, South Korea and the United States will accelerate efforts to press China to mull possible new sanctions, including an oil ban, if North Korea carries out another nuclear test or launches a long-range ballistic missile, several diplomats have said.

In addition to an oil embargo for the first time, other options in a new U.N. Security Council sanctions resolution could include measures such as globally banning the North's national airline, Air Koryo, prohibiting North Korean workers from working abroad, completely restricting its coal exports and ending seafood exports.

Currently, coal export restrictions are in place. Beijing, as the largest importer, recently agreed to the further suspension of coal transfers with its neighbor.