North Korea has denied that it sank a South Korean naval vessel near their disputed sea border late last month.
There has been growing speculation in the South that the ship had been hit by a North Korean torpedo, killing 46 sailors and raising fears it could cause conflict.
The North's KCNA news agency accused the government in Seoul of trying to put blame on its neighbour to boost support ahead of local elections in June.
'The puppet military warmongers, right-wing conservative politicians and the group of other traitors in South Korea are now foolishly seeking to link the accident with the north at any cost,' the North's KCNA news agency quoted an unnamed military commentator as saying.
'Another sinister aim sought by the puppet regime in floating the... story is to justify the persistent and anachronistic policy towards the DPRK (North Korea) and shirk the blame for having driven the inter-Korean relations to the worst crisis.'
South Korea, which has already brought some of the wreck to the surface, has said the blast that sank the vessel was caused by an external explosion.
Investigators from several countries are trying to determine what caused the 1,200-tonne Cheonan to split in half.
South Korea's defence minister said this month it may have been hit by a torpedo, immediately putting suspicion on the North.
