Kyiv's mayor Vitaly Klichko said the Ukrainian capital's authorities had approved an evacuation plan in case of a possible Russian invasion, Russian media reported on Saturday, citing the Kyiv administration's press service.

Meanwhile, Ukraine's foreign ministry urged Ukrainian citizens to keep calm and avoid panicking in the face of mounting worries that Russia was preparing to invade. 

"At the moment, it is critically important to remain calm, to consolidate inside the country, to avoid destabilizing actions and those that sow panic," the ministry said in a statement. 

(With input from AFP)