CAIRO (Reuters) – Egyptian rescue workers have found nine more bodies in the Mediterranean Sea a day after a boat carrying hundreds of migrants capsized, bringing the death toll so far to 52, two officials said on Thursday.

Egyptian authorities have arrested four crew members of the boat, which had been carrying almost 600 migrants, judicial sources said.

The boat sank on Wednesday off Burg Rashid, a village in Egypt’s northern Beheira province where the Nile meets the Mediterranean. Rescue workers have so far saved 169 people, which means the death toll could hit several hundred.

Prosecutors ordered the crew members jailed for four days while an investigation takes place. The rescued migrants have been released.

Egyptian Prime Minister Sherif Ismail pledged the government’s full support for the continuing rescue mission and said those responsible must be brought to justice. The military said in a statement it was conducting the rescue operation.

The boat had been carrying Egyptian, Sudanese, Eritrean and Somali migrants, officials said. It was not immediately clear where the boat had been heading, though officials said they believed it was going to Italy.

More and more people have been trying to cross to Italy from the African coast over the summer months, particularly from Libya, where people-traffickers operate with relative impunity, but also from Egypt.

Migrants who survived a shipwreck off the Greek island of Crete in June said their boat had set sail from Egypt. About 320 migrants and refugees drowned in that incident.

Some 206,400 migrants and refugees have crossed the Mediterranean this year, according to the International Organization for Migration.

More than 2,800 deaths were recorded between January and June, compared with 1,838 during the same period last year.

Some 1.3 million migrants reached Europe’s shores last year fleeing war and economic hardship, prompting bitter rows among European countries over how to share responsibility.

If they survive the perilous maritime journey, migrants this year face much tougher European Union border controls.

(Writing by Ahmed Aboulenein; Editing by Gareth Jones)