The European Union is considering additional measures against North Korea following the approval of harsh new sanctions by the U.N. Security Council in order to show solidarity with South Korea and Japan, both major trade partners, diplomats said.

EU foreign policy chief Federica Mogherini has welcomed Wednesday's U.N. unanimous vote to expand existing sanctions following North Korea's latest nuclear test and rocket launch, saying the bloc would update its sanctions regime.

"There is scope for the European Union to adopt additional autonomous restrictive measures to complement and reinforce the new U.N. measures," said a diplomatic note seen by Reuters on the latest discussions.