Survivors said as many as 500 people may have been killed when human traffickers hired to smuggle them into Europe purposely sank an overloaded ship off the coast of Malta last week. Italian and Maltese rescue workers picked up around a dozen survivors, including two who told officials that smugglers on a separate boat rammed the ship loaded with migrants after they refused to transfer to a smaller vessel.

The migrants were mostly from conflict-ridden areas in Africa and the Middle East, including from Palestine, Sudan, Egypt, Libya and Syria. Rescuers were able to save two children. A pair of Palestinians rescued after the shipwreck told officials they cast off from Damietta, Egypt, on Sept. 6 and switched boats a number of times. Smugglers rammed and capsized their ship about 300 miles off the coast of Malta.

Italian authorities estimate that 50,000 migrants have successfully made it to Italy via illegal Mediterranean crossings. The International Organization for Migration, a United Nations-affiliated agency, said the total number of migrants is actually double that, and at least 1,889 people have died in crossing attempts.