North Korea has flatly rejected calls by Seoul and Washington to assume responsibility for the March sinking of South Korea’s “Cheonan” naval corvette.

The Rodong Sinmun, the newspaper of the North’s Workers' Party of Korea, accused South Korean and U.S. officials in a statement Wednesday of hampering the resumption of the stalled six-way nuclear talks by continuing to focus on the Cheonan incident, in which Pyongyang claims no involvement.

The paper also said that although the North is doing its best to improve relations with South Korea, it will sternly deal with any moves that raise tensions on the Korean Peninsula.

After holding a summit with U.S. President Barack Obama in Seoul last Thursday, President Lee Myung-bak reaffirmed the point that North Korea must show a genuine and responsible attitude on the Cheonan incident. Lee said that such a development would be the starting point for an improvement in South-North ties.