VATICAN CITY, Holy See -- The number of migrants dying in the Mediterranean is an "open wound" for humanity, Pope Francis said Sunday after a week marked by a string of deadly shipwrecks.

At his weekly Angelus prayer, the 86-year-old pontiff offered his prayers for the 41 people reported missing on Wednesday by four survivors brought to safety on the Italian island of Lampedusa.

He recalled "with pain and shame" UN figures showing more than 2,000 migrants have lost their lives in the Mediterranean Sea since the start of the year.

"It is an open wound in our humanity," he told pilgrims gathered in St Peter's Square.

"I offer encouragement to the politicians and diplomats who are seeking to heal it, in a spirit of solidarity and brotherhood."

He also hailed "the commitment of all those who work to prevent shipwrecks and rescue sailors".

Francis -- who regularly urges better treatment of those who flee their homes for a better life elsewhere -- had this week already warned against becoming "indifferent" to the deaths.

A spokesman for the UN migration agency, the International Organization for Migration (IOM), said Saturday that "at least 2,060" migrants had lost their lives in the Mediterranean since January 1.

Of those, more than 1,800 died in the Central Mediterranean, the route from North Africa to Italy and Malta, he said -- more than twice as many as in the same period last year.

In the latest incident, two Tunisians including a baby died when their boat sank Saturday shortly after leaving the shores of the North African country, the coastguard said.

On Monday judicial officials reported the deaths of 11 migrants in a shipwreck off Sfax, with dozens more missing.

The eastern Tunisian port city located about 130 kilometres (80 miles) from  Lampedusa has emerged as a key migrant launchpad.

Meanwhile at least 30 migrants were reported missing on Sunday following two shipwrecks off Lampedusa, following days of bad weather.