Kazakh President Kassym-Jomart Tokayev has declared a two-week state of emergency in the Central Asian nation's biggest city Almaty and in the western Mangistau province where protests turned violent, his office said early on Wednesday.

The move includes an 11 pm to 7 am curfew, movement restrictions, and a ban on mass gatherings, according to documents published on the president's website.

"Calls to attack government and military offices are absolutely illegal," Tokayev said in a video address a few hours earlier.