Ukrainian President Volodymyr Zelenskyy urged Ukrainians to drive Russian troops out of the country.
"We have to go outside! We have to fight! Whenever there is an opportunity," Zelensky said in a video message.
Zelensky added that ordinary, unarmed people had opposed Russian units in several cities, including the southern port city of Kherson. He said it was important to prevent the establishment of more pro-Russian so-called "people's republics" on Ukrainian territory similar to the two currently self-declared in eastern Ukraine.
Addressing the people of the Donetsk and Luhansk regions, Zelenskyy said that if Russians "have not erased you memory through propaganda, if your eyes are not closed in fear - fight, for your rights, you freedom, for Ukraine."