Both North and South Korean churches councils are urging churches across the world to show solidarity on Aug. 13 with Korean churches by joining a "Sunday of Prayer for the Peaceful Reunification of the Korean Peninsula."

The theme for the prayer is based on the book of Romans 14:19 in the Bible: "Let us then pursue what makes for peace and for mutual upbuilding."

The day of prayer occurs two days before Liberation Day in Korea (15 August), during which people celebrate Korea's liberation from Japanese colonization, the World Council of Churches said in a statement.

The joint prayer was prepared by the Korean Christian Federation from North Korea and the National Council of Churches in Korea from South Korea.

The unification calls come at a time of lingering tension in the Korean Peninsula over North Korea's nuclear program and its repeated missile tests in recent months.

North Korea will be able to field a reliable, nuclear-capable intercontinental ballistic missile as early as next year, The Washington Post reported July 25.

It cited U.S. officials concluding in a confidential assessment that dramatically shrinks the timeline for when Pyongyang could strike North American cities with atomic weapons.

The Post reported that the new assessment by the ­Pentagon's Defense Intelligence Agency (DIA), which cuts a full two years off the consensus forecast for North Korea's ICBM program.

It triggered by recent missile tests showing surprising technical advances by the country's weapons scientists, at a pace beyond what many analysts believed was possible for the isolated communist regime.

The two Koreas are technically still at war as the 1950-1953 Korean War ended in an armistice with a cease-fire still to be signed.

World Council of Churches general secretary Rev. Olav Fykse Tveit and World Communion of Reformed Churches general secretary Rev. Chris Ferguson in a letter to their churches invited parishes and individuals across the world to pray for the reconciliation and healing of their divided Korean Peninsula.

"The prayer is an important part of our growing movement to overcome the antagonism that divides the Korean Peninsula and continue to open interaction between communities, churches and people," the letter reads.

"We believe churches across the world can, through prayer, help foster an environment in which peaceful reunification of the Korean Peninsula can flourish."