A migrant boat carrying about 700 passengers capsized Sunday in waters between North Africa and southern Italy, NBC News reported. 

Eighteen ships and four helicopters along with Italian navy vessels were dispatched to help rescue the victims after the overcrowded boat tipped over in Libyan waters south of Lampedusa, Italian Prime Minister Matteo Renzi said. Italian coast guard officials said 28 people have been rescued and 24 bodies have been recovered, but the worst is feared. 

"We fear that hundreds may have died in the capsizing," Carlotta Sami, spokeswoman for the United Nations Refugee Agency, told NBC News. 

Other reports say there were 950 passengers aboard the capsized vessel and that smugglers trapped many of them in the ship's cargo hold, according to the Associated Press. 

Survivors said the boat capsized when passengers rushed to one side of the boat as a merchant ship passed. 

"The first details came from one of the survivors who spoke English and who said that at least 700 people, if not more, were on board," Sami told SkyTG24 television.

"The boat capsized because people moved to one side when another boat approached that they hoped would rescue them."

If the death toll is as high as feared it would bring the number of migrants who have died crossing the Mediterranean to reach Europe since January to over 1,500. Scores more have died over the years risking their lives in overcrowded, unsafe boats with the hope of starting a better life in Europe. 

Officials and activists have pleaded with world leaders to do something to check human traffickers to prevent another mass tragedy. 

"A tragedy is unfolding in the Mediterranean, and if the EU and the world continue to close their eyes, it will be judged in the harshest terms as it was judged in the past when it closed its eyes to genocides when the comfortable did nothing," Maltese Prime Minister Joseph Muscat said according to NBC News.