The top nuclear negotiators of South Korea, the U.S. and Japan have discussed movements in North Korea related to the commemoration of the 70th anniversary of the Korean Armistice Agreement signing.

According to the foreign ministry, Kim Gunn held talks over the phone with his U.S. and Japanese counterparts Sung Kim and Takehiro Funakoshi on Tuesday and shared views on the North’s “Victory Day” proceedings and ways to respond to the launch of two short-range ballistic missiles overnight.

The phone discussions came a day after the North’s state-run Korean Central News Agency said that senior Chinese Communist Party official Li Hongzhong will lead a delegation to the North’s Victory Day celebrations.

The nuke envoys are likely to have assessed the upcoming visit by the Chinese delegation and the possibility of the North opening its borders.

The three officials jointly denounced the latest ballistic missile launch as a serious violation of multiple UN Security Council resolutions and a threat to regional and world peace and stability.

The officials agreed to sternly deal with any provocation by the North based on firm South Korea-U.S. defense readiness and security cooperation among Seoul, Washington and Tokyo while remaining alert to any further provocations.