Athens: Three people have died and 56 others were rescued after a migrant boat capsized off the southern Greek island of Gavdos, according to the state broadcaster. 

The Hellenic Coast Guard on Tuesday (local time) said a large-scale search and rescue operation was continuing in rough weather conditions to locate possible missing persons. Survivors were unable to confirm how many people had been on board when the vessel sank, reports Xinhua news agency, quoting the state broadcaster ERT.

The European Border and Coast Guard Agency (Frontex) is assisting Greek authorities in the ongoing operation. The nationalities of the victims and survivors have not yet been confirmed.

Gavdos, located south of the island of Crete, lies near routes often used by migrants attempting to reach Europe from North Africa. Greece has been one of the main entry points for irregular migrants and refugees into the European Union since 2015, when more than 1 million people crossed its borders, mainly from Turkey.

Over the years, hundreds have lost their lives in the Mediterranean Sea while trying to reach Europe in unseaworthy boats, prompting repeated calls from humanitarian organisations for stronger rescue coordination and safer migration routes.

Another boat tragedy struck a day earlier

A day earlier, four people died after a migrant boat sank off the Greek island of Lesvos.

Another seven migrants were rescued, the Greek coast guard said. A search and rescue operation was ongoing, despite being hindered by strong winds reaching force six on the Beaufort scale.

The exact number of people on board at the time of the incident remains unclear, as the survivors -- all Sudanese nationals -- do not speak English, making communication difficult.