ATHENS, GREECE -- A major search and rescue operation was underway in the eastern Aegean Sea Tuesday night after authorities received an emergency call from a boat carrying an unknown number of migrants, Greece's coast guard said.

The coast guard said 92 people had been rescued from the sea west of the small island of Halki, near Rhodes, by late Tuesday night and rescue crews were continuing to search for others.

Five nearby vessels and two military helicopters were participating in the search, as were one navy ship and five coast guard vessels.

The coast guard said authorities had received a distress call from the passengers on the vessel. There was no immediate information as to what kind of vessel it was, how many people were on board or what their nationalities were.

Thousands of people continue to make their way clandestinely to the Greek islands from the nearby Turkish coast, paying smugglers to ferry them in often unseaworthy, overcrowded inflatable dinghies or other vessels.