German Chancellor Angela Merkel and French president Emmanuel Macron will support tougher sanctions against North Korea following reports about the test of a hydrogen bomb.

In a phone conversation, the two leaders agreed that the recent provocation from Pyongyang was unprecedented and violated international law, La Libre reported. Merkel and Macron believe the European Union has to act together with the UN Security Council.

North Korea said they had conducted a successful test of a hydrogen bomb for long-range missile, the country’s sixth test of nuclear weapons.