Three people froze to death in two dinghies found drifting off the island of Evia, central Greece, on Saturday, carrying 57 illegal immigrants from Turkey, the Merchant Marine Ministry said.

Coast guard officials located the two inflatable vessels after a passing Turkish freighter tipped them off.

Authorities said the three migrants probably died because of the freezing wind blowing across the Aegean Sea but added that autopsies will be conducted.

Forty-one of the immigrants were from Pakistan and 12 from Bangladesh, while the remaining four people were from Albania. Authorities did not make public the identity of the men who died.

The ministry said the immigrants were undergoing medical examinations for signs of bird flu but initial tests show no cause for concern.

Two of the immigrants were hospitalized with hypothermia.

Authorities are questioning the four Albanian nationals, whom they suspect of leading the people-smuggling operation.