Ethiopia: Police, Muslim worshippers in 'unclear clashes' during Eid al-Fitr prayers
Unable to gain access because the stadium was full, some worshippers began to pray outside, in Meskel Square.
A member of the Addis Ababa High Council of Islamic Affairs told AFP that the cause of the confrontation was unclear.
A policeman fired tear gas at the crowd but "it was unintentional," the official said, quoting volunteers at the site.
"The policeman was evacuated by other policemen, but people were shocked and some started to chant slogans, the situation became uncontrollable".
Addis police issued a statement saying "a riot" had been caused by a "few individuals" and led to property damage, but order had now been restored.
"Police are calling on the community to remain calm," it said, adding that it would inform the public later about the cause of the disturbance.
AFP journalists said some demonstrators threw stones at police, shouting "Justice for Gondar" and "Don't burn our mosques, don't kill our people".
At least 20 people were killed last month in Gondar, a town in the northwestern region of Amhara, when Muslims were attacked by heavily-armed "extremist Christians," an Islamic group there says.
Stone-throwing demonstrators also smashed windows at a national museum on Meskel Square before calm was restored, AFP journalists said.
The Addis Islamic official told AFP that Eid al-Fitr prayers had taken place in Addis every year since the end of the Marxist-military Derg regime in 1991.
"This is the first time such incidents happen," the official said, adding that the Muslims attending the ceremonies were unarmed, as everyone was searched by police before they entered the venue.
"Muslims want this festival to pass in peace," the official said.
A country with a large mix of ethnicities, Ethiopia is majority Christian- of whom the most numerous are members of the Orthodox church- while around 30 percent of the population are Muslim.