Dozens of illegal immigrants were rescued Monday from a ship near the Greek island of Crete, while authorities were working to bring the vessel's over 300 other passengers to safety.

A total of 408 persons, mostly Syrians and including about 100 women and children, were aboard the 32-meter-long vessel when it sent out a distress signal.

The rescued immigrants have been transferred to a cargo vessel which first reached the area, along another Greek ship and a US warship from the nearby naval base on the island upon instructions of the Coast Guard.

A Greek Coast Guard speedboat and a Greek Navy frigate are leading the ongoing operation.

Greek Coast Guard officials said the ship faces no danger of capsizing or sinking at the moment and the operation runs smoothly.

It remained unknown where the ship's origin and destination, as well as why the distress signal was sent.

Each year, thousands of undocumented immigrants risked their lives to enter Greek waters aboard small derelict vessels, looking for a better future in Europe.

Over the past two years, according to Greek Shipping Ministry data, the Greek Coast Guard has rescued about 3,500 people in the Aegean Sea in such incidents.