North Korea’s ambassador to Germany Ri Si Hong has been summoned to Berlin in the wake of Pyongyang’s threats to conduct a “new form” of nuclear test.

“We strongly urge the government of North Korea to alleviate tensions and return to negotiations to resolve the nuclear issue,” Germany’s foreign ministry announced on the 7^th.

North Korea will face a “strong response” from the international community should they go ahead with a fourth nuclear test, the ministry warned.

The statement follows an official state visit from South Korean president Geun Hye last month, during which both countries agreed to cooperate in achieving Korean unification.