Former president Moon Jae-in (center) attends a memorial marking the 15th anniversary of President Roh Moo-hyun's death in Gimhae, 303 kilometers southeast of Seoul on Thursday.

Former South Korean President Moon Jae-in said Thursday the security situation on the Korean Peninsula is in a "crisis" phase where military conflicts could flare up "at any moment," as he called for diplomatic efforts to promote peace.

Moon made the remarks in a video message for a peace forum in Washington, as tensions have persisted on the peninsula with Pyongyang continuing its weapons tests in the absence of bilateral engagements with South Korea and the United States.

"The situation on the Korean Peninsula is in a state of crisis with military conflicts possible at any moment," Moon said during the forum hosted by the Korean American Public Action Committee, a nonprofit organization based in the US.

"Above all, diplomatic efforts to solve the problem through intergovernmental dialogues are crucial. Our role, which involves cooperation between parliaments and expanding public support, is also more important than ever," he added.

Known for the pursuit of cross-border rapprochement during his term from 2017-22, Moon voiced concerns that the situation on the peninsula has become "even more disturbing" against the backdrop of the "increasingly confrontational" international environment.

"Communication is not being restored. The Sept. 19 military agreement, which has been a stabilizing force on the Korean Peninsula, is being neutralized, and military tensions are at their highest," he said, referring to the 2018 inter-Korean tension reduction accord, which Pyongyang has walked away from.

"At such a time, it is urgent to strengthen the value of peace and make efforts to demonstrate peace on the Korean Peninsula in various ways," he added.

During his term, Moon pushed for an initiative to lay the foundation for lasting peace on the peninsula. But his drive lost steam amid a prolonged deadlock in nuclear negotiations between Washington and Pyongyang.

In a separate video message, Lee Jae-myung, the leader of the main opposition Democratic Party, vowed efforts to "uphold the value for lasting peace." (Yonhap)