Russia says it struck at weapons supplied to Ukraine by the West as US House Speaker Nancy Pelosi meets President Volodymyr Zelensky in Kiev during an unannounced visit.
Pelosi, the highest-ranking American leader to visit Ukraine since the start of the war, arrived on Saturday, leading a Congressional delegation.
She met Zelensky to vow continued support for Ukraine. "Our delegation traveled to Kiev to send an unmistakable and resounding message to the entire world: America stands firmly with Ukraine," Pelosi said in a statement.
Western nations have imposed broad economic sanctions on Russia and have been shipping increasing quantities of weapons
to confront Russian forces.
Pelosi said on Friday she hoped to pass a $33 billion aid package for Ukraine that President Joe Biden has requested "as soon as possible".
Russia's defense ministry said on Sunday it had carried out a missile strike on a military airfield near the port city of Odesa, destroying a runway and a hangar containing weapons and ammunition supplied to Ukraine by the US and European
On Saturday, Ukraine said Russian missiles had knocked out a newly constructed runway at Odesa's main airport.
Russia's defense ministry accused Ukraine's forces of shelling a school, kindergarten and cemetery in villages in the occupied southern Kherson region. The ministry said civilians had been killed and wounded.
Russian forces captured the town of Kherson, 100 km north of Crimea, in March and since then have mostly occupied Mariupol, a strategic eastern port city on the Azov Sea.
Ukraine's military said in a bulletin on Sunday that Russian forces were fighting to break beyond Kherson's administrative borders and prepare the way for attacks on the cities of Mykolayiv and Kryvyi Rih.
In Mariupol, Russia declared victory on April 21 even as hundreds of holdout Ukrainian troops and civilians took shelter in the city's bombed out Azovstal steel works, where they have been trapped with little food, water or medicine.
Russia's defense ministry said on Sunday that 46 civilians had left the area around the steel plant the previous day.
Zelenskiy said in a late-night video address that Russia was "gathering additional forces for new attacks against our military in the east of the country" and "trying to increase pressure in the Donbas".
Russia has repeatedly warned the West against continuing military assistance to Kiev, saying the weapons deliveries were “pouring oil on the flames of the war.”
'Russia should expropriate West's assets'
Russia's most senior lawmaker said on Sunday Moscow should confiscate property owned by Westerners in response to a proposal by the US president to transfer the frozen assets of Russia's elite to Ukraine.
Biden on Thursday asked Congress to allow the US state to seize more assets owned by Russian oligarchs and give the proceeds to Ukraine.
Duma Chairman Vyacheslav Volodin said the sumptuous yachts and villas of Russia's oligarchs had not helped Russian development but that the West appeared to be engaged in simple "theft".
"It is right to take mirror measures towards businesses in Russia whose owners come from unfriendly countries where such measures were taken: confiscate these assets," Volodin wrote on his Telegram channel.
"The proceeds from the sale should be used for the development of our country," he said. "A dangerous precedent has been created: it should hit the 'States like a boomerang."
Putin has repeatedly cautioned that Moscow will respond in kind. Thus far the Kremlin's toughest economic response has been to cut off gas supplies to Poland and Bulgaria and demand a new payment scheme for European buyers of gas.
Volodin singled out Lithuania, Latvia, Poland, and the United States as countries which were engaged in the "theft" of Russian assets.