Ukrainian President Volodymyr Zelensky said any constitutional changes that relate to security guarantees in the country would need to be decided through a referendum and not by him alone.
The Russian issued deadline for Mariupol authorities to surrender the city has now passed with Ukrainians rejecting the terms as a false choice.
Ukraine's president has announced restrictions on the activities of 11 political parties in the country, including some accused of having ties to the Russian state.
In a video message early Saturday, Ukrainian President Volodymyr Zelensky told Russia: "It's time to talk."
Former British PM Gordon Brown says Vladimir Putin should face an international tribunal over his actions in Ukraine.
Nine evacuation routes leading out of different Ukrainian cities, including the besieged southeastern city of Mariupol, have been agreed for Thursday, the Ukrainian government said.
Ukraine’s defense minister Oleksii Reznikov said Thursday that the Russian who bombed a theater being used as a civilian shelter in the besieged city of Mariupol is a “monster.”
Russian President Vladimir Putin, who has clamped down on any dissent since the invasion of Ukraine, on Wednesday blasted pro-Western Russians by calling them “national traitors” in a televised address.
The Russian invasion of Ukraine has largely stalled on all fronts, the UK Defense Ministry said Thursday on its official Twitter account.
People sheltering at a theater in Mariupol that was struck by a Russian bomb on Wednesday are emerging alive, according to a short statement posted on Facebook Thursday by the former head of the Donetsk region.
Russia's unmanned Luna-25 spacecraft has crashed into the Moon after spinning out of control, officials say.
Donald Trump has confirmed that he will not take part in Republican presidential debates with his rivals in the race for the White House.