Russian-led military troops will be deployed to help "stabilise" Kazakhstan amid anti-government demonstrations.
President Kassym-Jomart Tokayev called for support from the Collective Security Treaty Organization (CSTO) as nationwide unrest escalates, reports BBC.
The protests were first sparked by rising fuel prices, but have broadened to include other political grievances.
President Tokayev claimed the unrest was the work of foreign-trained "terrorist gangs".
However, Kate Mallinson, an expert on Central Asia at the foreign affairs think tank Chatham House in London, said the protests are "symptomatic of very deep-seated and simmering anger and resentment at the failure of the Kazhak government to modernise their country and introduce reforms that impact people at all levels".
The president has imposed a nationwide state of emergency that includes an overnight curfew and a ban on mass gatherings and has vowed a tough response to the protests.
In a televised speech in the early hours of Thursday, he said he had sought help from the CSTO - a military alliance made up of Russia and five ex-Soviet states to help stabilise the country.
Later on Wednesday the CSTO's chairman, Armenian Prime Minister Nikol Pashinyan, confirmed in a statement on Facebook that the alliance would send peacekeeping forces "for a limited period of time".
The US State Department said it is "closely following" the situation in Kazakhstan, with a spokesman urging restraint by authorities and protesters alike.
President Tokayev is only the second person to lead Kazakhstan since it declared independence in 1991. His election, in 2019, was condemned by the Organization for Security and Co-operation in Europe (OSCE) as showing scant respect for democratic standards.
Much of the anger on the streets, however, seems to have been aimed at his predecessor, Nursultan Nazarbayev, who has held a powerful national security role since stepping down. On Wednesday, he was fired in a bid to subdue the growing unrest.
Protesters had been heard chanting Mr Nazarbayev's name, while a video showing people attempting to pull down a giant bronze statue of the former leader has been shared online. According to BBC Monitoring, the now-dismantled monument appears to have stood in Taldykorgan, Mr Nazarbayev's home region.
Staff at Kazakhstan's main airport had to flee anti-government demonstrators, who have also targeted government buildings.
Protesters gathered at the mayor's office in Almaty before eventually storming it. Videos on social media showed a plume of smoke rising from the building, while gunfire could also be heard.
The city's police chief, Kanat Taimerdenov, said "extremists and radicals" had attacked 500 civilians and ransacked hundreds of businesses.
Water cannon were used against protesters in the western city of Aktobe. There are reports that security forces have sided with protesters in some places.
However, getting a clear picture of what is happening in the central Asian nation is proving difficult. The interior ministry released figures of reported casualties among the security forces, but there were no equivalent reports of any injuries or deaths among protesters amid what monitoring groups have described as a "nation-scale internet blackout".
Other attempts to end the protests, which began on Sunday when the government lifted the price cap on liquefied petroleum gas which many people use to power their cars, causing it to double in cost, have been made.
As well as Mr Nazarbayev's dismissal, the entire government has resigned.