Dozens have been killed and injured in Ethiopia's Oromia region after security forces confronted protesters at a festival, witnesses say.
Some people died in a panicked stampede after police employed tear gas, rubber bullets and baton charges, they said.
Thousands had gathered for a religious festival in Bishoftu, 40km (25 miles) from the capital Addis Ababa.
Some reports said police responded after anti-government protesters threw stones and bottles. Others said demonstrators were entirely peaceful.
Ethiopia's government said in a statement that "lives were lost", adding: "Those responsible will face justice".
An Oromo activist, Jawar Mohamed, is quoted as saying nearly 300 people were killed and many more injured. He said troops and a helicopter gunship had opened fire, driving people off a cliff and into a lake.
There has been no independent confirmation of this.
Police fire tear gas to disperse protesters during Irreecha, the thanks giving festival of the Oromo people in Bishoftu town of Oromia region, Ethiopia,
Demonstrators show the Oromo protest gesture sign during Irreecha, the thanks giving festival of the Oromo people in Bishoftu town of Oromia region, Ethiopia,
But many said the demonstrators were protesting peacefully about political and economic marginalisation
The US had already expressed concern about excessive use of force against protesters before Sunday's violence
There have been months of deadly clashes in Ethiopia recently.
People in the Oromia and Amhara regions have complained about political and economic marginalisation.
The US has expressed concern about what it termed the excessive use of force against protesters.
Source: BBC
