Ukrainian officials have announced their armed forces have made big advances in regions Russia declared annexed including a key village in the Kherson region.
Officials also report that Ukrainian forces are consolidating their progress in the north-east.
This comes as Russia formally annexed four Ukrainian regions in a move seen as a violation of international law.
The formal annexation of the Donetsk, Luhansk, Kherson and Zaporizhzhia regions follows the ratification of the treaties recognising the territories as Russian by the Russian parliament.
Russia invaded Ukraine on February 24 and has since been sanctioned by the EU and the US.