Deployment comes in response to an appeal from Kazakhstan President Tokayev to help stabilise the Central Asian country in the wake of “terror attacks” and mass protests sparked by a fuel price rise.
Russian paratroopers have been deployed to Kazakhstan as part of a peacekeeping force that includes troops from four other former Soviet republics, the secretariat of the regional military bloc Collective Security Treaty Organisation (CSTO) has said.
The CSTO secretariat released a video on Thursday showing service members embarking on a cargo plane that took off from the military airfield in the Moscow region.
The deployment came in response to an appeal from the president of Kazakhstan to help stabilise the Central Asian country amid a wave of protests sparked by a fuel price rise.
The secretariat said the peacekeepers' main tasks would be to protect important state and military facilities and help the Kazakh law and order forces.
The peacekeeping forces will total around 2,500 people, the RIA news agency quoted the secretariat of the bloc as saying.
Kazakhstan's President Kassym-Jomart Tokayev says his country is under attack from "terrorists" and has appealed to a Russia-led military alliance for help.
'Memories of situations to be avoided'
Meanwhile, the European Union’s foreign policy chief said on Thursday that External military assistance to Kazakhstan brings back "memories of situations to be avoided".
Expressing the EU's "great concern" over developments in Kazakhstan, Josep Borrell said on Twitter that the rights and security of civilians must be guaranteed.
The United States warned Russian troops deployed to the country against taking control of the former Soviet republic's institutions, saying the world would "watch for rights violations."
"The United States and, frankly, the world will be watching for any violation of human rights," State Department spokesman Ned Price said.
The UN Human Rights chief Michelle Bachelet on Thursday said authorities in Kazakhstan must stick to strict “requirements of necessity and proportionality” after police said dozens of protestors had been killed in rioting in Almaty.
Biggest crisis in decades
Long seen as one the most stable of the ex-Soviet republics of Central Asia, energy-rich Kazakhstan is facing its biggest crisis in decades after days of protests over rising fuel prices escalated into widespread unrest.
Thousands took to the streets in Almaty and in the western province of Mangystau, saying the price rise was unfair given oil and gas exporter Kazakhstan's vast energy reserves.
Armed protesters have fought running battles with government forces, with officials saying 748 security officers have been wounded and 18 killed, including two who had their heads cut off. Security forces in Kazakhstan killed dozens of protesters trying to storm government buildings overnight.