Italian coast guard and navy ships, aided by an Irish naval vessel, saved more than 500 migrants from smugglers' boats in the Mediterranean off Libya on Saturday, Italian and Irish officials said.

The rescues are the latest by a multi-national patrol south of Sicily that has saved thousands this week.

The Irish military said the vessel Le Roisin, deployed earlier this month in the humanitarian search and rescue operations, saved 123 migrants from a 12-meter-long (40-foot) rubber dinghy and recovered a male body.

An Italian navy ship saved 101 migrants on another rubber dinghy, and a ship of the Italian coast guard, which coordinates all the rescues by various navies, cargo vessels and humanitarian organization boats, reported rescuing 322 migrants from a boat in distress.

Meanwhile, with migrant shelters filling up in Sicily, the Italian navy vessel Vega headed toward Reggio Calabria, a southern Italian mainland port, bringing 135 survivors, along with 45 bodies, from a rescue a day earlier. The Vega was due to dock on Sunday.

At the Vatican Saturday, Pope Francis told several hundred children, among them many migrants, who came from the Italian south to see him that migrants "aren't a danger but they are in danger."

Among the audience was a Nigerian youth, who lost his parents in 2014 as the family tried to reach Italy by sea. Francis has repeatedly expressed dismay that some European nations have refused to accept migrants, fleeing poverty or war, and have even thrown up fences and other barriers to thwart the arrivals from journeying northward after reaching the continent's southern shores.

In France, an Afghan migrant died after being hit by a truck near the coastal city of Calais.

Pas-de-Calais region Secretary-General Marc Del Grande said the 25-year-old was hit while he and about 50 other migrants were laying branches on the highway in an effort to slow traffic. Migrants gathered in Calais routinely try to hop aboard trucks in an effort to sneak into Britain, which lies just across the English Channel.