Two people drowned and four were missing at sea and feared dead after two merchant ships collided in rough seas off the Italian coast today, Italian officials said.

A Turkish ship with 11 crew members sank after the collision with a vessel carrying a Belize flag in poor visibility a mile from the Italian Adriatic port of Ravenna, a coastguard official said.

The mayor of Ravenna Fabrizio Matteucci said on Italian state television that the dead and missing were all Turkish men from the ship Gokbel which sank after the collision with the Belize-flagged Lady Aziza at around 0800 GMT.

"There are two victims and four missing," he said, adding that he had received the latest information from the coastguard leading the rescue operation, which was hampered by "prohibitive" sea conditions and fog.

The names of the dead and missing have not been released.

Earlier on Sunday the coastguard said one person was dead and two missing, and they were trying to save four people they had located in the sea.

Five members of the Turkish ship have been rescued and are in good condition and there were no casualties among the crew of the other ship, Matteucci said.