A coalition of South Korean pro-unification groups said Saturday it has proposed to its North Korean counterpart to hold contact this week to work out details to jointly mark the 15th anniversary of a historic inter-Korean summit of leaders in 2000 and the 70th anniversary of Korea's liberation from Japan's colonial rule.

Both sides had agreed to celebrate together the June 15, 2000 inter-Korean summit and the Korean Peninsula's liberation from Japanese colonial rule in 1945 when they met in the Chinese city of Shenyang earlier this month. But they failed to agree on details, including where to hold them.

The South Korean civilian coalition said both sides meet as soon as possible to discuss details.

"We've proposed holing a two-day meeting with North Korea starting Tuesday in the North Korean city of Kaesong for further discussions on the planned events," Seoul's committee in charge of the preparation for the joint events said in a news release.

"We also call on both the South and North Korean governments to provide proactive support and cooperation to host the joint events," it added.

The 2000 inter-Korean summit produced a landmark agreement, known as the June 15 Joint Declaration, which outlines reconciliation and economic cooperation between the two Koreas, which remain technically at war as the 1950-53 Korean War ended in a truce, not a peace treaty.

No joint celebrations of the anniversaries have been held since 2008 as cross-border relations deteriorated. (Yonhap)