Lampedusa, Italy - Three vessels carrying around 450 would-be immigrants were heading Monday for the southern Italian island of Lampedusa, navy officials said.

The Italian navy picked up SOS signals transmitted from two of the vessels, both drifting some 70 nautical miles south-east of Lampedusa, Captain Cosimo Nicastro said.

A coastguard patrol boat has been dispatched to rescue the would-be immigrants whose nationality has yet to be established, Nicastro said.

Another coastguard rescue mission was under way for the over 50 occupants of the third vessel, which was spotted by an Italian trawler some 55 nautical miles south of Lampedusa, Nicastro said.

Each year thousands of would-be immigrants from Africa and Asia try to enter Europe illegally by crossing the Mediterranean Sea and attempting to land on Italy's extensive coastline.

These journeys, which are mostly carried out using ramshackle vessels, often have fatal consequences. (dpa)