South Korea’s president called on NATO and several of the bloc’s member states to oppose North Korea’s nuclear and missile activities on Tuesday, while Seoul reached an agreement with the organization to boost cooperation on nonproliferation and cybersecurity.

In a meeting with NATO Secretary-General Jens Stoltenberg on the sidelines of the security alliance’s summit in Lithuania, Yoon Suk-yeol emphasized that the international community must respond firmly to Pyongyang’s “illegal nuclear and missile provocations” and requested NATO’s support, Seoul’s presidential office said in a press release.

In response, Stoltenberg expressed concernabout North Korea’s nuclear and missile development and stated