Russia pounded Ukrainian forces with air strikes and artillery in the east and the south, targeting command centres, troops, and ammunition depots, the Russian defence ministry said.
Russian forces are intensifying efforts to capture Severodonetsk, the final Ukrainian strongpoint in the eastern Luhansk region.
Luhansk Governor Serhiy Haidai said the only functioning hospital in Severodonetsk has just three doctors and supplies for 10 days.
Ukrainian President Volodymyr Zelenskyy said the Russian army was also attacking the city of Sloviansk, in the Donetsk, but Ukrainian forces were holding off its advance in both major centres. Sloviansk is critical to Russia’s objective of capturing all of eastern Ukraine.
Russia claims to have taken prisoner nearly 2,500 Ukrainian fighters from the besieged Azovstal steel plant, and concerns have grown about their fate.
Moscow released video of Russian troops taking into custody Serhiy Volynskyy, commander of the Ukrainian Navy’s 36th Special Marine Brigade, which was one of the main forces defending Azovstal.
A prominent member of Russia’s parliament, Leonid Slutsky, said Moscow was studying the possibility of exchanging the Azovstal fighters for Viktor Medvedchuk, a wealthy Ukrainian with close ties to Russian President Vladimir Putin who faces criminal charges in Ukraine.
The Ukrainian mayor of Mariupol warned it is facing a health and sanitation “catastrophe” from mass burials in shallow pits across the ruined city as well as the breakdown of sewage systems.
The Russian military has said it destroyed a major consignment of Western arms in Ukraine’s Zhytomyr region, west of Kyiv, using sea-launched Kalibr cruise missiles.
Russian missiles also struck fuel storage facilities near Odesa on the Black Sea coast and shot down two Ukrainian Su-25 aircraft and 14 drones, the military said.
Ukraine has ruled out agreeing to a ceasefire with Russia and said Kyiv would not accept any deal with Moscow that involved ceding territory.
US President Joe Biden signed a bill to provide nearly $40bn in aid for Ukraine as part of efforts to boost military support over Russia’s invasion, the White House said.
Polish President Andrzej Duda arrived in Ukraine on an unannounced visit and will address the country’s parliament on Sunday.
Portuguese Prime Minister Antonio Costa said he pressed Western countries for multiple-launch rocket systems, which he said “just stand still” in other countries yet are key to Ukraine’s success.
In an interview with the Telegraph, British foreign secretary Liz Truss said she wants to see Ukraine’s neighbour Moldova “equipped to NATO standard” to guard against any threats from Russia.
Turkish President Recep Tayyip Erdogan, who has objected to Sweden and Finland joining NATO, held phone calls with the leaders of the two countries and discussed his concerns about “terrorist” groups there.
Zelenskyy said he talked to Italian Prime Minister Mario Draghi and stressed the importance of more sanctions on Russia and unblocking Ukrainian ports.
Russian energy giant Gazprom halted gas exports to neighbouring Finland, the latest escalation of an energy payments dispute with Western nations.
Russia’s transport minister said Western-backed sanctions have “practically broken” logistics in the country.