Dozens killed in stampede after police fire warning shots at protest

The state broadcaster put the death toll at 52, citing regional officials. The opposition also said at least 50 people were killed at the annual festival where some people had chanted slogans against the government and waved a rebel group's flag.

Sporadic protests have erupted in Oromiya in the last two years, initially sparked by a land row but increasingly turning more broadly against the government. Since late 2015, scores of protesters have been killed in clashes with police.

The developments highlight tensions in the country where the government has delivered stellar economic growth rates but faced criticism from opponents and rights groups that it has reduced political freedoms.

Thousands of people had gathered for the annual Irreecha festival of thanksgiving in the town of Bishoftu, about 40 km (25 miles) south of the capital Addis Ababa.

Some protesters waved the red, green and yellow flag of the Oromo Liberation Front, a rebel group branded a terrorist organisation by the government, witnesses said.

When police fired teargas and guns into the air, crowds fled and created a stampede, some of them plunging into a deep ditch.

The witnesses said they saw people dragging out a dozen or more victims, showing no obvious sign of life. Half a dozen people, also motionless, were seen being taken by pick-up truck to a hospital, one witness said.

"As a result of the chaos, lives were lost and several of the injured were taken to hospital," the government communications office said in a statement, without giving figures. "Those responsible will face justice."

Merera Gudina, chairman of the opposition Oromo Federalist Congress, told Reuters at least 50 people had died, based on details provided by families of the victims.

He said the government tried to use the event to show Oromiya was calm. "But residents still protested," he said.

The government blames rebel groups and dissidents abroad for stirring up the protests and provoking violence. It dismisses charges that it clamps down on free speech or on its opponents.

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Protesters had chanted slogans against the Oromo People's Democratic Organisation, one of the four regional parties that make up the Ethiopian Peoples' Revolutionary Democratic Front, which has ruled the country for quarter of a century.

In a 2015 parliamentary election, opposition parties failed to win a single seat - down from just one in the previous parliament. Opponents accused the government of rigging the vote, a charge government officials dismissed.

Protests in Oromiya province initially flared in 2014 over a development plan for the capital that would have expanded its boundaries, a move seen as threatening farmland.

Scores have been killed since late in 2015 and this year as protests gathered pace, although the government shelved the boundary plan earlier this year.