Greek authorities were conducting a major search and rescue operation Wednesday for dozens of people missing at sea east of the island of Karpathos after a boat reportedly carrying up to 80 migrants sank during the night.

The coast guard said that by early morning 29 people, all men, had been rescued from the sea 33 nautical miles (38 miles, 61 kilometers) east southeast of Karpathos, a southeastern island between Rhodes and Crete.

The survivors were from Afghanistan, Iraq and Iran, and told authorities there had been roughly 60 to 80 people on board the vessel when it went down, the coast guard said.

Those rescued said the boat had set sail from the Antalya area on the southern Turkish coast and had been heading to Italy when it ran into trouble during the night.

Two coast guard patrol boats, a Greek navy vessel, an air force helicopter and at least three ships sailing nearby were participating in the search and rescue efforts, the coast guard said.

“The search is continuing with unreduced intensity,” said Shipping and Island Policy Minister Giannis Plakiotakis, under whose jurisdiction the coast guard lies. “The protection of human life is our daily concern and absolute priority,” he said, adding that more than 6,000 people had been rescued in 145 search and rescue operations over the past two years.

A video released by Greek authorities showed two people being plucked from the sea and winched to a helicopter in a night-time rescue, and then walking to a waiting ambulance once they had been airlifted to shore.

The most common sea route for asylum-seekers from the Middle East, Asia and Africa has been from Turkey to nearby Greek islands. But with Greek authorities increasing patrols in the Aegean, and facing repeated and persistent reports of summarily deporting new arrivals to Turkey without allowing them to apply for asylum, many are now skirting the Greek islands and attempting to take the much longer, and more dangerous, route directly to Italy. Greek authorities deny they carry out illegal summary deportations of asylum-seekers.