(CNN)About 300 migrants are feared dead after their boats sank in the Mediterranean Sea, the U.N. refugee agency said Wednesday.
The incident is just the latest in a long series of disasters involving migrants risking dangerous journeys to seek a better life.
The migrants left Libya on Saturday in rubber boats, the International Organization for Migration said.
Some may have died without entering the water. Initial reports suggest 29 people died Sunday on one boat, mainly from hypothermia, said Andrej Mahecic, spokesman for the U.N. High Commissioner for Refugees.
More than 110 survivors arrived on the Italian Island of Lampedusa after being rescued by the Italian coast guard and a merchant vessel, he said.
"They confirmed to UNHCR that they had left on Saturday from Libya on rubber dinghies and had been at sea for days, without food and water," Mahecic said.
Only two out of 107 passengers survived on one boat, and seven out of 109 people survived on another dinghy, the U.N. agency said.
The Italian Coast Guard is continuing to search for a fourth dinghy, but rough sea conditions are hampering efforts.
"This is a tragedy on an enormous scale and a stark reminder that more lives could be lost if those seeking safety are left at the mercy of the sea," said Vincent Cochetel, UNHCR Europe bureau director.
An often deadly voyage
Worldwide, more than 40,000 migrants have died in their journeys since 2000, the International Organization for Migration said in September.
Over half of them were trying to get to Europe. About 6,000 deaths occurred along the U.S.-Mexico border.
And the situation is getting worse in Europe. Italy has recorded at least 50 migrant deaths this year, compared with 12 by this point last year, UNHCR spokesman Adrian Edwards told journalists in Geneva, Switzerland.
The migrants' primary country of origin? Syria, where millions have tried to flee the country's four-year civil war.
Syrians accounted for 22% of the migrants arriving in Italy in January, Edwards said.
Many of the maritime tragedies involve human traffickers transporting migrants in overcrowded, unseaworthy boats.
"Limited opportunities for safe and regular migration drive would-be migrants into the hands of smugglers, feeding an unscrupulous trade that threatens the lives of desperate people," IOM research chief Frank Laczko said last year.
"Undocumented migrants are not criminals. They are human beings in need of protection and assistance, and deserving respect."