Ukrainian President Volodymyr Zelenskyy says Russia will bury its prospect for negotiations with its own hands if it holds referendums in Russian-controlled regions of eastern and southern Ukraine.

Pro-Russian separatists plan to hold votes on joining Russia from Friday through Tuesday.

In a video message on Thursday, Zelenskyy called the referendums a "sham" and a "farce." He said Russian leaders were using the same tactic as they did in Crimea and Donbas in 2014.

Zelenskyy also said Ukrainian intelligence knew that Russia planned to mobilize 300,000 people in the reserve before Russian President Vladimir Putin made the announcement.

He said he believes Russian leaders are preparing to take up to a million men into the army but are not speaking about it.

Zelenskyy also said, "due to mobilization, Russia's war against Ukraine for the majority of Russian citizens is not something on TV or on the Internet, but something that has entered every Russian home."

He urged Russians not to remain silent and called on them to protest against the Putin administration to prevent more soldiers from dying or becoming wounded and maimed.