ATHENS, Greece — Greece’s coast guard says a search and rescue operation is under way for more than a dozen passengers from a yacht that sank off the coast of the island of Milos.

Coast guard spokesman Nikolaos Kokkalas said 17 passengers had been on board the roughly 30-meter-long (98-foot-long) yacht.

Two helicopters, three coast guard patrol boats, a private boat and two nearby vessels were involved in the rescue operation, and Kokkalas said survivors were being picked up from the Aegean Sea.

It was not immediately clear who had been on board the yacht or what their nationalities were. The cause of the sinking west and northwest of Milos has not yet been determined.