(AFP) - Thousands of migrants have died after suffering "extreme" abuse while crossing Africa, according to a UN report on Wednesday that estimated 72 people perish each month on the continent's routes.

There has been considerable focus on the thousands lost at sea while trying to cross from Africa to Europe, but a new report found that routes from West and East Africa up towards the Mediterranean can be equally perilous.

Entitled "On this journey, no one cares if you live or die", the report published jointly by the UN refugee agency and the Danish Refugee Council's Mixed Migration Centre (MMC) details horrific realities many face along the way.

Most migrants making such journeys experience or witness "unspeakable brutality and inhumanity" by smugglers, traffickers, militias and sometimes state actors, the UNHCR said.

In 2018 and 2019 alone, at least 1,750 people died, corresponding to an average of 72 a month or more than two deaths each day, "making it one of the most deadly routes for refugees and migrants in the world," the report found.

"For too long, the harrowing abuses experienced by refugees and migrants along these overland routes have remained largely invisible," UN refugee chief Filippo Grandi said in the statement.

The report, he said, documents "killings and widespread violence of the most brutal nature, perpetrated against desperate people fleeing war, violence and persecution."

Nearly a third of those who die along these overland routes tried to cross the Sahara desert. Others perished in the south of war-ravaged Libya, while another deadly route crosses conflict-ridden Central African Republic and Mali.

- 'Appalling conditions' -

Those who survive are often left severely traumatised.

This is particularly true for the many who pass through Libya, where random killings, torture, forced labour and beatings are widespread, the report found.

Tens of thousands of refugees and asylum seekers, often sub-Saharan African and Asian migrants hoping to make it across the Mediterranean, have been stranded in chaos-wracked Libya, now a key route for illicit migration to Europe.

And many of those who try to cross the Mediterranean are stopped and turned back by the Libyan coastguard.

More than 6,200 refugees were forced to disembark in Libya so far this year alone, the report said, stressing that many are then detained in "appalling conditions".

Women and girls, but also men and boys, face a high risk of rape and other sexual abuse along the various routes, in particular at checkpoints, in border areas and during desert crossings, the report found.

Smugglers were the main perpetrators in North and East Africa, while in West Africa police and security forces were held responsible for a quarter of the reported sexual assaults.

Around a third of those who reported witnessing or surviving sexual violence said it had occurred in more than one location.

"Strong leadership and concerted action are needed by states in the region, with support from the international community, to end these cruelties, protect the victims and prosecute the criminals responsible," Grandi said.

© Agence France-Presse