Hundreds of people gathered in the center of Kondopoga, in Russia's Karelia Republic, on Saturday to demand that all Chechens and other ethnic minorities from the North Caucasus region be expelled from the area following a fatal clash in a city restaurant Wednesday night.
The restaurant, which was reportedly owned by Chechens, was attacked and then torched, while a marketplace was also ransacked.
Prime Minister Pavel Chernov said he ordered cabinet members to make an all-out effort to prevent similar incidents in the future.
He said earlier the violence occurred against the backdrop of a campaign targeting the constitutional rights of people from Chechnya, where federal forces have waged two campaigns in the last 12 years against militants and other people from the Caucasus.
He said a failure to take action against led to the weekend's unrest.
The republic's Prosecutor's Office said it opened two criminal cases into the killing of two Kondopoga residents and the subsequent violence.
Police have detained 109 people Sunday afternoon, and remanded about 25 of them into custody on charges of hooliganism.
A police representative said two suspects from the North Caucasus were detained in connection with the restaurant killings.
Chechnya's prime minister said earlier Monday that inaction by local authorities was to blame for the weekend violence.
"If the police in Kondopoga were able to stop at least serious crimes, including major brawls, then the current crisis would not have happened and nationalists would not have received new trump cards in their campaign," said Ramzan Kadyrov, Chechnya's premier and the son of late president, Akhmad Kadyrov.
Kadyrov said the Chechen community in the city, which is about 1,000 kilometers (600 miles) northwest of Moscow, asked for help from the government of Chechnya.
However, Karelia Governor Sergei Katanandov, who arrived in Kondopoga Sunday, said authorities already met with rival groups to ease tensions, and would make every effort to resolve the situation.
"We will not permit ethnic hostility," he said. "I will not leave until you all calm down and until I see that the city is calm."