The Ukrainian parliament, the Verkhovna Rada, on Wednesday adopted a statement on the inadmissibility of holding "referendums" in the "Luhansk People's Republic (LPR)", "Donetsk People's Republic (DPR)", Kherson and Zaporizhzhia regions, according to deputy chairman of the Parliament's finance committee, Yaroslav Zheleznyak.

The four regions in Ukraine will hold referendums on joining Russia between September 23 and 27, Russian news agency TASS reported on Tuesday.

On Wednesday, Russian President Vladimir Putin announced a partial military mobilization.

Ukrainian President Volodymyr Zelenskyy said the partial mobilization shows that Russia has "problems with officers and other military personnel," in an interview with German media Das Bild.

Zelenskyy also said he does not believe Russia will use nuclear weapons, after Putin said Moscow would use all means to protect its territory.