The death toll from a capsized fishing boat carrying migrants off the coast of southern Greece has risen to 79, the Greek coast guard has announced.
A large-scale search and rescue operation was underway on Wednesday morning after the boat, which is believed to have been transporting up to 400 people from near the Libyan port of Tobruk to Italy, capsized during the night in strong winds some 75 kilometers (46 miles) southwest of Greece's southern Peloponnese region.
So far, 104 people have been confirmed rescued and taken to the Greek town of Kalamata. They received dry clothes and medical attention in shelters set up by ambulance services and the United Nations Refugee Agency.
Four people have been hospitalized with symptoms of hypothermia.
Authorities initially put the death toll at 32, before increasing it to 59 and then higher still to 79. Fears remain that it could yet increase even more.
How many people are still missing?
The search, which involves six coast guard vessels, a navy frigate, a military transport plane, an air force helicopter, several private vessels and a drone from the European Union border protection agency, Frontex, is ongoing.
A Greek Migration Ministry source told the AFP news agency that, according to the coastguard, there could have been "hundreds" of people on board the boat. "We fear there will be a very large number of missing persons," the official said.
The International Organization for Migration estimated that "up to 400" people may have been on board, noting in a tweet: "We fear more lives were lost."
Authorities said the vessel was first spotted in international waters early on Tuesday evening by an aircraft belonging to EU border agency Frontex and two nearby ships.
The Greek coast guard said the people on board — none of whom were wearing life jackets and who did not immediately disclose their nationalities — had initially "refused any help."
What's the bigger picture?
Greece is one of the main routes into the European Union for refugees and migrants from the Middle East, Asia and Africa.
About 72,000 refugees and migrants have arrived so far this year in Europe's frontline countries Italy, Spain, Greece, Malta and Cyprus, according to United Nations data, with the majority landing in Italy.
Mediterranean smugglers are increasingly taking larger boats into international waters off the Greek mainland to try to avoid local coast guard patrols. On Sunday, 90 migrants were rescued in the area after they made a distress call.
And in a separate incident on Wednesday, a yacht with 81 migrants on board was towed to the south coast of the Greek island of Crete after authorities received a distress call.
On the other side of the Mediterranean, Libyan authorities launched a crackdown earlier this month, with activists saying that several thousand migrants, including Egyptians, Syrians, Sudanese and Pakistanis, have been detained.
Many Egyptians have reportedly been deported back to their home country through a land crossing point.