The incident adds to a series of attacks that have raised fears of a growing Southeast Asian piracy menace.
The unnamed tanker was travelling from Singapore to Thailand and it was attacked near the Malaysian resort island Tioman in the South China Sea, the International Maritime Bureau's (IMB) Piracy Reporting Centre said.
The ship's crew were locked in the engine room as the pirates siphoned off the tanker's cargo of lubricant oil to another vessel.
The
