Last week, Seoul released the findings of a report which concluded that a North Korean submarine had fired a torpedothat sank the Cheonan corvette, killing 46 sailors.

The North has denied the accusation.

Lee said the president would also demand a response from the North.

"President Lee Myung-bak may mention the name of the leader Kim Jong-il [in the conclusion of the speech]," he said.

International response

Washington has called for an "international response" to the sinking,without specifying what form this might take.

An international response could range from fresh Security Council sanctions on North Korea, although those might be opposed by China, to a statement of condemnation by the world body.

A range of sanctions are already in place against North Korea for its missile and nuclear tests of recent years.

South Korea has repeatedly said it would not strike back at the North, aware that would frighten away investors already weary about the escalating tension on the divided peninsula.

The two Koreas are still technically at war because their 1950-53 conflict
ended with an armistice, not a peace treaty.