Thousands of people have marched in the Ethiopian capital to protest the killing of many Ethiopian Christians in Libya.

The government-supported gathering at Addis Ababa's Meskel Square turned violent as stone-throwing protesters clashed with the police, who arrested many.

Ethiopians raised slogans including one that said "We want revenge for our sons' blood," referring to Ethiopians seen being beheaded or shot in a video released by the Islamic extremist group Islamic State.

Some of the protesters directed their anger at Ethiopia's government, seen by some as not doing enough to raise the living standards of the most vulnerable people.

Ethiopian Prime Minister Hailemariam Desalegn said smugglers were to blame for encouraging poor people to pursue what he called a "death journey."