A boat carrying as many as 500 people capsized and caught fire off the Italian island of Lampedusa, the nation's coast guard told CNN on Thursday.
At least 110 people died, a doctor with the local health department said. Antonio Candela said that 154 people had been rescued in the ongoing operation.
Lampedusa, not far from Sicily and the closest Italian island to Africa, has become a destination for tens of thousands of refugees seeking to enter European Union countries -- and such deadly shipwrecks are all too common.
The latest boat to sink is thought to have been carrying up to 500 people. Those aboard include Eritreans, Somalis and Ghanaians, the coast guard said, and the boat is believed to have launched from Libya's coast.
CNN forecasters said there were some gusting winds and showers Thursday morning in the region but no weather conditions significant enough to be likely to sink a boat.
According to Italian media reports, the vessel sank near Rabbit Beach, also known as Rabbit Island, which was recently voted one of the best beaches in the world by Trip Advisor.
The survivors are being taken to Lampedusa's main port, where authorities have the facilities to help them.
The bodies of those who didn't make it are also being moved there. Images from the scene showed some lined up in body bags on a quayside.
The head of the U.N. refugee agency, Antonio Guterres, praised the efforts of the Italian coast guard but said he was "dismayed at the rising global phenomenon of migrants and people fleeing conflict or persecution and perishing at sea."
Another 13 men drowned off Italy's southern coast Monday when they attempted to swim ashore, the U.N agency said in a statement.
It is working with countries in the region to find "effective alternatives" so people don't risk their lives trying to make perilous journeys by sea, it said.
Last week, the Italian coast guard rescued a ship bound for Lampedusa from Tunisia that had 398 Syrian refugees on board.
There is generally a spike in migrants coming to the island -- which has 6,000 full-time residents -- in the summer because the seas are calmer.
Migrants who spoke to CNN's Eric Marrapodi last week in Lampedusa said they typically spent a day or two at sea in boats that are barely seaworthy.
Those who arrive generally have no papers and seek asylum in Italy. They spend anywhere from a day to a week on Lampedusa before moving to another city on the mainland.
At the detention center where they first take the migrants, the coast guard said, they had 1,250 migrants in a space designed for 250.
A Navy doctor said that typically those who arrive are treated for dehydration, sun exposure, and gasoline burns, because they're so packed into the boats the fuel splashes and burns the skin.
A Navy commander said the service has been working with Thuraya, a satellite phone company, to try to make sure that it gets the coordinates of migrants sent out on boats by traffickers before they come to harm.
Just under 115 kilometers (70 miles) from Tunisia, the island has been the first point of entry to Europe for more than 200,000 refugees and irregular migrants who have passed through the island since 1999.
But boats carrying migrants often are in peril at sea.
In recent years, the Italian Coast Guard says it has been involved in the rescue of more than 30,000 refugees around the island.
Izabella Cooper, a spokeswoman for the European Union's border control agency, Frontex, told CNN that migrants are often sent to sea in overcrowded vessels without the engine power to make such a long and dangerous journey.
Since the start of the year, Frontex -- which supports the efforts of individual EU member states -- has helped save more than 16,000 lives in search-and-rescue operations, she said.