Some 46 sailors were killed in the sinking incident.
The Korean Central News Agency (KCNA) said on Tuesday that Pyongyang was to ban all South Korean ships and planes from its territorial waters and airspace.
“The Committee for the Peaceful Reunification of Korea… formally declares that from now on it will put into force the resolute measures to totally freeze the inter-Korean relations, totally abrogate the agreement on non-aggression between the North and the South and completely halt the inter-Korean cooperation,” KCNA quoted the official statement as saying.
Earlier on Tuesday, the North warned South Korea of a military response for allegedly trespassing in its waters. Pyongyang says Seoul has deliberately made the move, arguing that it seeks another military conflict in the region.
South Korea, however, has denied entering the North’s waters.
Tension has been on the rise on the Korean peninsula ever since a torpedo sank a South Korean warship on March 26, killing 46 sailors.
Seoul says the torpedo was fired from a North Korean submarine. The North, however, has rejected the claim as “smear campaign,” insisting that its navy did not torpedo the South Korean ship.
South Korea has responded by stopping all trade relations with the North.
This is while Russia and China have called for restraint in order to prevent an escalation of the crisis between the two neighboring countries.