Kazakhstan's security forces have detained a total of 7,939 people as of Monday over last week's unrest, the Interior Ministry said, the worst bout of violence in the Central Asian nation's post-Soviet history.

Government buildings were briefly captured or torched in several cities last week as initially peaceful protests against fuel price increases turned violent.

Authorities have blamed the violence on "extremists" and "terrorists" some of whom they say were foreigners.

Karim Masimov, former head of the National Security Committee, was detained on suspicion of treason last week, days after President Kassym-Jomart Tokayev dismissed him.

Tokayev has also sacked his cabinet, issued shoot-to-kill orders to end the unrest and declared a state of emergency in the oil-rich nation of 19 million. He also asked a Russian-led military bloc to send in troops, who the government says have been deployed to guard strategic objects.

Russian and state media reported 164 people were killed during the clashes, citing a government social media post. But health and police authorities did not confirm the figure and the social media post was then deleted.

"I think there was some kind of a conspiracy involving domestic and certain foreign destructive forces," Secretary of State Yerlan Karin told state television on Monday, without naming any suspects.