Pope Francis on Sunday called on authorities to stop human traffickers operating in the Mediterranean, as he expressed his sorrow over last week's migrant boat disaster off Italy's Calabrian coast, in which dozens of people were killed.

"I renew my appeal to prevent such tragedies from happening again. May traffickers of human beings be stopped," the pope said in his weekly address to crowds in St. Peter's Square.

Local authorities said 70 bodies had so far been recovered following the incident. The migrants had departed from Turkey and were from countries including Afghanistan, Pakistan, Iran, Somalia and Syria.

"May journeys of hope never again turn into journeys of death, may the clear waters of the Mediterranean no longer be bloodied by such dramatic accidents," the pope said.

Around 80 people survived after the boat broke up and sank in rough seas near Steccato di Cutro, a resort on the Calabria region's eastern coast. Authorities estimated it had carried up to 200 migrants. 

Three alleged traffickers were arrested this week and prosecutors began looking into the way emergency services responded to the disaster, after accusations that authorities were slow to react.

"I pray for the many victims of the shipwreck, for their families and for those who survived," the pope said.

Right-wing Italian Prime Minister Giorgia Meloni, who this week called on fellow European Union leaders to do more to halt illegal immigration, praised the pope's remarks. 

The government was "continuing to deploy all necessary forces to combat human traffickers and stop deaths at sea," she said in a post on Facebook.