On Friday, powerful explosions were heard in Kyiv and fighting raged in the east after Ukraine claimed responsibility for the sinking of the Russian Navy's Black Sea flagship.
The explosions appeared to be among the most significant in Ukraine's capital region, since Russian troops pulled back from the area earlier this month in preparation for battles in the south and east.
Ukraine said it hit the Moskva missile cruiser with a Neptune anti-ship missile. A Russian defense ministry said that the Soviet-era ship sank on Thursday as it was being towed to port after a fire and explosions.
The ministry said over 500 crew were evacuated, without acknowledging an attack.
The ship's loss comes as Russia's navy continues its bombardment of Ukrainian cities on the Black Sea nearly 50 days after it invaded the country to root out Nazis. Ukrainian President Volodymyr Zelenskyy paid tribute to all those who stopped the progress of the endless convoys of Russian military equipment. They showed that Russian ships can go down to the bottom. There were no immediate reports of damage after the explosions reported in Kyiv, Kherson in the south, the eastern city of Kharkiv and the town of Ivano-Frankivsk in the west.
Ukraine's armed forces said Russian attacks on the towns of Popasna and Rubizhne, both north of the port city of Mariupol, had been repulsed and a number of tanks and other armored vehicles had been destroyed. Reuters was not able to verify the reports.
Whatever the cause of Moskva's loss, it is a setback for Russia and a major boost for Ukraine's defenders.
Russia s navy has fired cruise missiles into Ukraine, and its Black Sea activities are crucial to supporting land operations in the south and east, where it is trying to take full control of Mariupol.
The United States said it did not have enough information to determine whether Moskva was hit by a missile.
Jake Sullivan, national security adviser, said that Russia was a big blow to Russia as a result of the way this unfolded.
Russia launched a special military operation in Ukraine on February 24, in part to dissuade Kyiv and other former Eastern Bloc countries from joining NATO.
But in more setbacks for Moscow, Finland, which shares a long border with Russia, and nearby Sweden are considering joining the U.S.-led military alliance.
Moscow warned on Thursday that if Sweden and Finland joins, Russia would deploy nuclear weapons and hypersonic missiles in a Russian enclave in the heart of Europe.
The threat of Russia potentially using nuclear weapons in Ukraine should not be lightly taken lightly, but the agency has not seen much evidence reinforcing that concern, according to William Burns, CIA director.
More than 4.6 million people have been forced to flee abroad and killed or wounded by Russia, according to Kyiv and its allies.
Russia said on Wednesday that more than 1,000 Ukrainian marines had surrendered from one of the units still holding out in Mariupol. Ukrainian officials did not make a statement.
If taken, Mariupol would be the first major city to fall to Russian forces since they invaded Ukraine, allowing Moscow to reinforce a land corridor between separatist-held eastern Donbas areas and the Crimea region it seized and annexed in 2014.
Hundreds of thousands of people were believed to have been killed in Mariupol, where efforts were under way to evacuate civilians.
Russia's defense ministry said on Thursday that 815 people had been evacuated from the city over the past 24 hours. Ukraine said that figure was 289.