Security forces in Kazakhstan say they've killed dozens of protesters in the country's largest city Almaty.
Russia has sent paratroopers to help combat anti-government demonstrations in the former Soviet nation. State media in Kazakhstan said 13 officers had been killed in the violence and more than 350 injured.
In recent days, the protests, which were triggered by a rise in fuel prices, have spread to major cities including the capital Nursultan and morphed into a wider movement against President Kassym-Jomart Tokayev.
His government has resigned in response to the protests, during which more than 1,000 people have been injured, according to Kazakhstan's health ministry.
The doubling of the price of liquefied petroleum gas (LPG) was the catalyst for thousands to take to the streets. But there's also wider anger at Tokayev's predecessor, Nursultan Nazarbayev, who ruled the nation for nearly 30 years after the fall of the Soviet Union.
Despite stepping down in 2019 and personally picking Tokayev as his successor, many think he still calls the shots in the tightly controlled state.
One protester, Rafik Zharylkasyn, said years of pent-up anger had boiled over: "Lots of versions of what happened here have been told. You have to understand what has happened here. The coiled spring has now been unleashed after 30 years. Look, all of us have been fired upon."
On Wednesday, protesters stormed the presidential residence and mayor's office in Almaty and set them on fire, with President Tokayev vowing "maximum toughness" in his response.
Tokayev requested help from Russia and other former Soviet states to deal with what he called a foreign-inspired uprising.
"The terrorist mobs are essentially international. They underwent serious training abroad and their attack of Kazakhstan can be and should be viewed as an act of aggression. For this reason, I reached out to the heads of the Collective Security Treaty Organization (CSTO) states today to assist Kazakhstan in overcoming this terrorist threat," he said.
The CSTO also includes Belarus, Armenia, Kyrgyzstan and Tajikistan. Neither the organization nor Tokayev has provided any proof of foreign involvement in the protests.
Vladimir Zainetdinov, press secretary of the CSTO confirmed that Armenia, Belarus, Kyrgyzstan, Russia and Tajikistan had provided contingents of "peacekeeping forces" for a limited time period in order to "stabilize and normalize the situation."
In an interview with CGTN in Russia he said: "The main tasks of the collective peacekeeping forces of the CSTO will be the protection of important state and military facilities, the assistance to the law enforcement of the Republic of Kazakhstan in stabilizing the situation and returning it to the legal framework."
"From the Russian Federation, the Collective Peacekeeping Forces of the CSTO included units and military units of Airborne troops."
The United Nations said it was concerned by the violence and was monitoring the situation closely.
"I think it's very important for all involved in these current events to exercise restraint, refrain from violence, and promote dialogue in addressing all of the pertinent issues," said Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres.
On Thursday, the UK said it was in talks with allies about a unified response.
"We condemn the acts of violence and destruction of property in Almaty and we will be coordinating further with our allies on what further steps we should take," UK Foreign Secretary Liz Truss told parliament.
The European Union said it was "ready and willing to support a dialogue in the country" and urged Russia to respect Kazakhstan's sovereignty.
"The violence must be stopped. We are also calling for restraint from all parties and a peaceful resolution of the situation," said a EU spokesperson.
Kazakhstan is rich in natural resources, including oil and coal and is the world's largest producer of uranium, which is used in nuclear power generation. The price of the metal shot up by 8 percent in response to the violence.
Despite its vast mineral reserves, many Kazakhs feel they've been left behind by an elite that's profited from decades of oil-led growth.