"That is why we call on all sides to use restraint."

Schaefer said Berlin was convinced a "military option" could not be "the answer in the quest for a nuclear weapon-free Southeast Asia".

He urged the international community to "thoroughly implement" the latest round of sanctions against North Korea approved by the United Nations Security Council.

And he backed a call by US Secretary of State Rex Tillerson to resume talks with Pyongyang if it halts ballistic missile tests.

"We must all continue our diplomatic efforts -- it is the only way to ensure that the threat of the illegal North Korean nuclear weapons programme can be contained," he said.

Trump sharply intensified his rhetoric against North Korea on Tuesday, threatening "fire and fury" over its weapons programmes.

North Korea raised the stakes just hours later, saying it was considering missile strikes near US strategic military installations on the Pacific island of Guam.