A French oil tanker with 17 sailors on board has gone missing off Ivory Coast and was suspected to have been hijacked by pirates, an international piracy monitoring group said Monday according to dpa. "Operation is ongoing to locate the missing vessel," a spokesman for the Kuala Lumpur-based International Maritime Bureau said. Luxembourg authorities identified the vessel as the Gascogne, owned by the French group Sea-Tankers and flying a Luxembourg flag. "Since Sunday, no contact could be made with the tanker," the Luxembourg government said.