Hundreds of would-be migrants from North Africa who were trying to reach Europe are missing and feared drowned after their boat capsized about 120 miles south of the Italian island of Lampedusa. Officials say it could be the largest-ever such tragedy on the Mediterranean.

Officials engaged in a major air-and-sea rescue in the Mediterranean say that so far 28 people have been rescued along with the recovery of 24 bodies. As many as 700 are still missing after the overcrowded fishing boat capsized and sank overnight. Although it is not uncommon for such migrant boats to come to grief in the Mediterranean, the sheer loss of life in the latest incident appears to be particularly large.

Adrian Edwards, a spokesman from the United Nations High Commissioner for Refugees in Geneva, tells NPR's Weekend Edition Sunday that some 20 ships from Italy and Malta, as well as several helicopters were engaged in the search.

"There are many, many bodies in the water.," Edwards says.

"We are hoping there are survivors among them," he tells Weekend Edition. "But, it's really a matter of very great concern," adding that if the numbers of dead reported are confirmed, "we are looking at the single largest tragedy so far on the Mediterranean."

The Times of Malta reports that the migrants went overboard when they rushed to one side of the boat to alert a passing ship. A Maltese patrol boat was helping in the rescue effort and the island's prime minister, Joseph Muscat, said: "They are literally trying to find people alive among the dead floating in the water."

The disaster comes only a week after 400 others were reported dead in a similar capsize near Lampedusa.

The Associated Press notes: "The capsizing comes amid a wave of migrants trying to leave Libya for Italian shores. So far, at least 900 have died trying this year."

For many people fleeing North Africa, including the ongoing fighting in Libya, the island of Lampedusa represents the closest outpost of European Union territory from which they hope to move onward and settle elsewhere in the EU.

Reuters writes: "The new deaths fueled calls for a stronger response from Europe to the increasingly deadly migrant crisis playing out in the Mediterranean. International aid groups and Italian authorities have [criticized] Europe's so-called "Triton" border protection operation, which recently replaced a more comprehensive Italian search-and-rescue mission.

"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 was quoted by Reuters as saying.

In February, the U.N. High Commissioner for Refugees Antonio Guterres reiterated a call for the European Union to expand operation "Triton."

Updated at 2:45 p.m. EDT. EU To Discuss Situation on Monday:

Reuters quotes EU foreign policy chief Federica Mogherini as saying the foreign ministers of the EU would discuss the issue at a meeting Monday in Luxembourg.

Update at 8:30 EDT. Even More May Have Been Aboard; U.N. Responds

A survivor told Italian prosecutors that more migrants than previously estimated may have been on board the ship, the AP reports.

The wire service says the survivor indicated the ship contained 950 people, "including hundreds who were locked in the hold by smugglers," but that this account has not been confirmed.

Meanwhile, the U.N. Secretary-General's office issued a statement saying Secretary-General Ban Ki-Moon is "shocked and deeply saddened" by reports of the event.

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