Washington (CNN) -- The U.S. Navy tried to get permission to board a North Korean merchant vessel that it suspected was carrying illicit weapon technology in the South China Sea, the Pentagon confirmed Monday.
It was denied permission, but the United States kept an eye on the vessel, which later turned around and returned to North Korea, the Pentagon said. The incident occurred late last month, it said.
The MV Light is registered and flagged in Belize but was believed to be manned by a North Korean crew, according to Col. David Lapan, a Pentagon spokesman.
According to Lapan, on May 26, the merchant vessel was hailed by the USS McCampbell, which requested permission to board the ship and inspect its cargo. The ship's master denied the request, telling the Navy ship that it was a North Korean ship, according to the Pentagon.
Lapan said the vessel was in violation of international law in refusing the boarding.
It was believed the ship might have been heading to Myanmar, he said. Several U.N. resolutions permit the boarding of ships suspected of carrying banned weapons cargo such as ballistic missile parts or technology.
The McCampbell maintained surveillance of the vessel for several days. On May 29 the vessel turned around and headed back to a North Korean port, with the United States maintaining surveillance all the way, Lapan said.
He would not specify how that surveillance was maintained, but the Navy is known to use surveillance aircraft at sea, and U.S. intelligence satellites regularly monitor North Korean ports.