A boat carrying migrants capsized Wednesday in the Mediterranean off Egypt's north coast, drowning 42 people and prompting a search operation in which another 150 were rescued, officials said.

The vessel overturned off the port city of Rosetta, police and health officials said, with the total number of people on board not clear.

The tragedy comes months after the EU's border agency Frontex warned growing numbers of migrants bound for Europe were turning to Egypt as a departure point for the perilous sea journey.

Smugglers often overload the boats, some of them scarcely seaworthy, with passengers who have paid for the journey.

Forty-two people died in Wednesday's boat accident, health ministry spokesman Khaled Megahed told AFP, updating an earlier toll of 30.

Emergency workers had rescued 150 passengers, according to officials in the police force and health ministry.

Hospitals were being prepared to receive more casualties, the ministry said.

Egypt's Prime Minister Sharif Ismail ordered police to arrest the smugglers responsible, a cabinet statement said.

The accident came a day after the military said it stopped a boat carrying 68 migrants before it set off from Egypt's northwestern coast, not far from Rosetta.

More than 10,000 people have died attempting to cross the Mediterranean for Europe since 2014, according to the United Nations.

Asylum-seekers have been seeking other ways to reach Europe since March, when Balkan countries closed the popular overland route and the EU agreed a deal with Turkey to halt departures.

“Egypt is starting to become a departure country,” Frontex chief Fabrice Leggeri said in an interview with the Funke group of German regional newspapers in June.