Lesya Orobets from the Batkivshchyna political party said other people had been seriously injured.
"Three bodies of our supporters are in the building. Another seven are close to dying (because of wounds),' she said on her account on Facebook social network.
Tensions run high in the heart of Kiev after a protest march in the Mariinsky park near the Ukrainian parliament spiraled off into massive clashes between activists and riot police. Interior Ministry troops are reported to be under attack, with protesters throwing fire crackers and handmade explosives at the police.