Death and atrocities are constant companions for migrants who journey through Africa in the hope of reaching Europe, the UN Refugee Agency (UNHCR) and the Mixed Migration Centre said in a report published on Wednesday.
At least 1,750 people died on land routes within Africa in the past two years, according to the Geneva-based UN agency and the think tank that is part of the non-governmental Danish Refugee Council.
In comparison, the onward sea migration route from Libya to southern Europe claimed more than 2,500 lives during that period.
More than a quarter of the economic migrants and refugees who die within Africa lose their lives in the Sahara desert, the report said.
Other lethal hotspots include Mali's capital Bamako, Agadez in Niger, and several locations in Libya.
"Refugees and migrants have reported being subjected to brutal violence, including being burnt with hot oil, melted plastic, or heated metal objects, being electrocuted, tied in stress positions, and experiencing and witnessing repeated sexual violence," the report said.
Such crimes are committed by people smugglers as well as by security officials.
Sexual crimes do not only happen to women and girls, but also to men and boys, especially at security check points and during desert crossings, according to the UNHCR and the Mixed Migration Centre.
"For too long, the harrowing abuses experienced by refugees and migrants along these overland routes have remained largely invisible," UNHCR chief Filippo Grandi said, demanding regional action as well as international support to tackle these problems.