India's coast guard detained a “suspicious” North Korean cargo ship after a six-hour chase off the country's southeastern coast, a coast guard official said Saturday, but a preliminary search of the vessel revealed it was carrying sugar and not illicit cargo. The MV Mu San was pursued by coast guards who opened fire above the vessel after it attempted to flee from an island in the Andaman and Nicobar group where it had dropped anchor without permission Wednesday, said Cmdr. Vijay Singh, a spokesman for the Indian coast guard. Indian army, navy and intelligence officials had begun “initial investigations,” including inspecting the ship which was said to be carrying 16,5000 tonnes of sugar, the official added, without elaborating. Meanwhile, a senior Coast Guard Officer K.R. Nautiyal told the Times of India newspaper “several things were amiss” about the North Korean vessel. “She shouldn't have dropped anchor here in the first place. She did not respond to our signals and her logbook was found to be vague,” he said in the report published Saturday. The incident comes in the wake of a United Nations resolution passed in June that allows other countries to request boarding and inspection of North Korean ships suspected of transporting illicit cargo - though the vessels do not have to give permission. The resolution was passed to punish North Korea for its recent nuclear and missile tests. The ship was escorted to Port Blair, the capital of the Andaman and Nicobar islands, and Indian officials were questioning the 39 North Koreans on board, Singh told The Associated Press by phone. The vessel picked up its cargo at a port in Thailand, and was also thought to have made a stop in Singapore. “What also made us suspicious was that their passports were not stamped in Singapore and they were not very clear about their destination,” he said. North Korean ships have in the past been accused of clandestinely ferrying nuclear materials, missile parts and arms to trouble spots across the world. The US Navy tracked a North Korean cargo vessel, the Kang Nam 1, in June. The ship, which was believed destined for Myanmar, suddenly turned back on June 28. North Korea is believed to earn money from selling missile technology and weapons. The detention of the North Korean ship comes days after a news report, quoting Myanmar defectors, said Pyongyang was helping fellow pariah state Myanmar build a secret nuclear reactor and plutonium extraction plant for an atomic bomb.