North Korea's Foreign Ministry said Panama should release the crew detained in the seizure of a freighter carrying missile components because no drugs or illegal cargo were aboard.
A Foreign Ministry spokesman, who was not named by the official Korean Central News Agency, said: "The Panamanian investigation authorities rashly attacked and detained the captain and crewmen of the ship on the plea of 'drug investigation' and searched its cargo but did not discover any drug."
Decades-old missile components were found on board.
North Korea said: "This cargo is nothing but ageing weapons which (North Korea) are to send back to Cuba after overhauling them according to a legitimate contract."
North Korea said: "The Panamanian authorities should take a step to let the apprehended crewmen and ship leave without delay."