The Japanese and German leaders agreed Tuesday to work together to seek a new and tougher U.N. sanction resolution against North Korea following its powerful nuclear test over the weekend, a Japanese government official said.

North Korea's sixth nuclear test Sunday poses a threat "not only to Japan but also to the whole world," German Chancellor Angela Merkel told Prime Minister Shinzo Abe during their telephone conversation Tuesday night, according to the official.

The two also agreed on the need to fully and strictly implement U.N. Security Council resolutions aimed at making North Korea give up its nuclear and missile ambitions. Merkel promised she will call on other European Union member states to act together with Japan on the issue, the official said.

Their talks came as part of a flurry of diplomatic activities the Japanese government is engaging in following Pyongyang's nuclear test, in which it claimed it detonated a hydrogen bomb that can be mounted on an intercontinental ballistic missile.