Southeast Asian nations have expressed “grave concern” over North Korea’s nuclear tests last year and subsequent ballistic missile launches that have racheted tensions on the Korean Peninsula.

Foreign ministers of the Association of Southeast Asian Nations, or ASEAN, issued their statement on Friday on the eve of the leaders’ annual summit in Manila, saying the instability on the Korean Peninsula “seriously impacts the region and beyond.”

The 10-nation regional bloc also urged North Korea and all parties concerned “to exercise self-restraint in order to de-escalate the tension and refrain from actions that may aggravate the situation.”