Colombian officials have detained the captain of a Chinese ship bound for Cuba for illegally carrying explosives and other arms.
The ship was stopped over the weekend in the Caribbean port of Cartagena, the attorney general's office said.
About 100 tonnes of gunpowder, almost three million detonators and some 3,000 cannon shells were found on board the Da Dan Xia, officials said.
But according to the ship's records, it was carrying grain products.
"The documentation that the captain had in regards to the merchandise that was being transported did not correspond to what we found," said Luis Gonzalez, national director of the Colombian attorney general's office.
Wu Hong, the Chinese captain, would be charged with weapons trafficking, he added.
Chinese foreign ministry spokeswoman Hua Chunying said the captain had not violated any international rules.
"It is completely normal military trade co-operation," she said.
Ms Hua said China was "communicating with the parties on this matter".
The Da Dan Xia is operated by China's largest shipping company, Cosco Shipping.
It was impounded and searched for 48 hours before the order to arrest the captain was given.
Colombian media reported that the ship was also carrying pipes used in mining and had stopped in Cartagena to unload them.
According to the reports, counter-narcotics police searched it after they had received a tip-off about the munitions on board.
The ship was due to make another stop in the Colombian port of Barranquilla before sailing on to Cuba, its itinerary suggested.
The Cuban authorities have not yet commented.
The incident comes almost two years after a North Korean crew was detained in Panama for illegally transporting war material from Cuba to North Korea through the Panama canal.
Most of the crew and the ship were allowed to return to North Korea six months later after its owners agreed to pay a fine.
The ship's captain, the first officer and the political officer were later absolved of a charge of endangering public security.