Ukraine recaptured more territory around Kyiv from Russian soldiers as they moved away from the capital, while a disputed cross-border strike in Russia complicated peace talks.
In the hamlet of Dmytrivka to the west of the capital, smoke was still rising from the wrecks of tanks and the bodies of at least eight Russian soldiers lay in the streets, Reuters correspondents saw.
"From one side we were hearing the tanks shooting at us, and from the area of Bucha was a massive mortar shelling," said resident Leonid Vereshchagin, a business executive, referring to a town to the north.
Ukrainian forces went on to take back Bucha, its mayor said on Friday in a video that appeared to be filmed outside the town hall. The advances followed several days of Ukrainian gains around Kyiv and in the north.
In southwest Ukraine, anti-air defences thwarted an attempted attack on critical infrastructure in the Black Sea port of Odesa, the Ukrainian military said. Reuters could not immediately verify the account.
Odesa's governor, Maksym Marchenko, said three missiles had hit a residential district, causing casualties. He said the missiles were fired from an Iskander missile system in Crimea, the southern Ukrainian peninsula annexed by Russia in 2014.
Russia denies targeting civilians.
'Constant explosions'
President Vladimir Putin sent troops on 24 February for what he calls a "special operation" to demilitarise Ukraine. The West calls it an unprovoked war of aggression that has killed thousands and uprooted a quarter of Ukraine's population.
Moscow said Ukrainian helicopters struck a fuel depot in the Russian border city of Belgorod, a logistics hub for its war effort, causing a huge fire. Ukraine denied responsibility for the incident, the first of its kind in the five-week-old war.
Kremlin spokesperson Dmitry Peskov said the incident could jeopardise Ukrainian-Russian peace talks, which resumed on Friday by video link. Russia will strengthen its western borders so it won't "cross anyone's mind to attack," Peskov said later.
Hours after the blaze began at the oil depot, an eyewitness reached by telephone in Belgorod, who asked not to be identified, said aircraft were flying overhead and there were continuous explosions from the direction of the border.
"Something is happening. There are planes and constant explosions in the distance."
Security camera footage, from a location verified by Reuters, showed a flash from what appeared to be a missile fired from low altitude in the sky, followed by an explosion on the ground.
Ukraine's top security official said Russia's accusations were not correct. Ukraine's defence ministry earlier had declined to confirm or deny involvement.
"Ukraine is currently conducting a defensive operation against Russian aggression on the territory of Ukraine, and this does not mean that Ukraine is responsible for every catastrophe on Russia's territory," said ministry spokesperson Oleksandr Motuzyanyk.
A Russian threat to cut off gas supplies to Europe unless buyers paid with roubles by Friday was averted for now, with Moscow saying it would not halt supplies until new payments are due later in April.
Photo: Ukrainian State Emergency Service / AFP Caption: This handout picture released on March 30, 2022 by the State Emergency Service of Ukraine shows rescuers conducting search operations and dismantling the debris of a government building in Mykolaiv, which was hit by Russian rockets the previous day