North Korea has sent a letter to the U.N. Security Council recommending that an investigation into the sinking of the "Cheonan" be jointly conducted by the two Koreas.

North Korean Ambassador to the U.N. Sin Son-ho sent a letter to the council Tuesday urging council members to take steps so that South Korea and the U.S. would accept a dispatch of North Korean inspectors to look into the Cheonan incident.

The North also insists that the Cheonan be discussed at high-level inter-Korean defense talks that exclude the Military Armistice Commission.

In response, South Korea sent a letter to the Security Council saying that the attack on the Cheonan violated the armistice treaty and therefore it must be addressed by the commission.