In one of the deadliest shipwrecks involving migrants trying to reach Europe from northern Africa this year, at least 50 people from Libya drowned and another 16 survived after their boat capsized in the Mediterranean Sea off the Tunisian coast.

The state-run Tunis Afrique Presse agency said the death toll had risen on Saturday (AEST) to at least 70 people 
after the boat they were on left neighbouring Libya hoping to reach Europe, where renewed warfare between rival factions has gripped the capital Tripoli in the past five weeks.

The boat sank 64km off the coast of Sfax, south of the capital Tunis, as fishing boats attempted to rescue survivors in the water, the Tunisian agency said.

The Tunisian Defence Ministry said the boat had left from the Libyan port of Zouara on Thursday aiming to reach Italy.

Navy units have recovered only three bodies so far, it said in a statement.

“Another tragedy in the Mediterranean,” the International Organisation for Migration said.

📍BREAKING: 16 survivors reported so far in deadly shipwreck of migrants off the coast of #Tunisia https://t.co/cYZsIT51TR pic.twitter.com/d0lMdNMQj5

— IOM – UN Migration 🇺🇳 (@UNmigration) May 10, 2019

Libya’s western coast is a main departure point for migrants from across Africa hoping to reach Europe by paying human traffickers, though numbers have dropped due to an Italian-led effort to disrupt smuggling networks and support the Libyan coast guard.

Italy’s Interior Minister Matteo Salvini let a charity boat carrying 30 rescued migrants dock at an Italian port but said the vessel would be impounded and not let out to sea again.

The migrants, including two pregnant women, a baby and four unaccompanied minors, were picked up by the Mare Jonio on Thursday off the coast of Libya as their rubber boat was sinking.

The death toll from a migrant boat that capsized off Tunisia has risen to 65.

It is one of the deadliest shipwrecks this year.

The UN says that for every 3 people that reached EU shores after leaving Libya this year, 1 person died. pic.twitter.com/Dcmz8ivdqF

— AJ+ (@ajplus) May 10, 2019

Earlier on Friday, UNHCR spokesman Babar Baloch said the United Nations had repeatedly voiced its concerns about the lack of boats to pick up migrants and refugees fleeing from “the horrendous and horrible situation” in Libya, calling on governments to step in.

On its website, UNHCR’s Special Envoy for the Mediterranean Vincent Cochetel said: “This is a tragic and terrible reminder of the risks still faced by those who attempt to cross the Mediterranean”.

The UNHCR said this latest tragedy was the highest loss of life since 117 people died or went missing in January, with a total of 164 deaths in total up until the end of April this year.

“Across the region, we need to strengthen the capacity of search and rescue operations,” Mr Cochetel said, as staff prepared to help survivors with emergency shelter, food, blankets and medicines.

“If we don’t act now, we’re almost certain to see more tragic events in the coming weeks and months.”

Dozens drown as migrant boat capsizes off Tunisia: Survivors say the boat left Libya on Thursday and ran into trouble during strong waves. https://t.co/OQAFHZSSoP pic.twitter.com/3WB5avIWSb

— AfricaNewsPress (@AfricaNewsPress) May 10, 2019

-with agencies