Rome: As many as 500 migrants are feared to have drowned after traffickers rammed and sank their boat in what the International Organisation for Migration (IOM) described on Monday as “the worst shipwreck in years”.

Horrific details of the shipwreck near Malta, told to IOM by survivors, came after dozens of African migrants were reported missing and feared dead after their boat sank off the coast of Libya on Sunday.

“If this story, which police are investigating, is true, it would be the worst shipwreck in years... not an accident but a mass murder, perpetrated by criminals without scruples or any respect for human life,” IOM said in a statement.

Two Palestinians plucked from the water by a freighter on Thursday after their boat capsized told IOM that around 500 passengers had been on the vessel, which was wrecked on purpose by people smugglers.

According to the survivors, the Syrian, Palestinian, Egyptian and Sudanese migrants set out from Damietta in Egypt on September 6, and were forced to change boats several times during the crossing towards Europe.

The traffickers, who were on a separate boat, then ordered them onto a smaller vessel, which many of the migrants feared was too small to hold them.

When they refused to cross over to the new boat, the furious traffickers rammed their boat until it capsized, the survivors told the maritime organisation.

“Two survivors brought to Sicily told us that there had been at least 500 people on board. Nine other survivors were rescued by Greek and Maltese ships, but all the rest appear to have perished,” Flavio Di Giacomo, IOM’s spokesman in Italy, said.

Both Palestinians spent a day and a half in the water, one wearing a life jacket and the other holding on to a lifebuoy with other migrants, all of whom perished, including a young Egyptian boy who hoped to make money in Europe to pay for his father’s heart operation, the organisation said.

In a separate incident, dozens were feared drowned after a boat carrying 200 migrants sank off Libya, with only 36 survivors rescued.

This year has seen a surge in the numbers of migrants attempting to make the hazardous crossing from North Africa and the Middle East to Europe.

According to the UN’s refugee agency (UNHCR), more than 2,500 people have drowned or gone missing attempting the crossing in 2014, including over 2,200 since the start of June.