A strike on a crowded market in the Russian-occupied city of Donetsk in eastern Ukraine left at least 25 people dead and 20 wounded on Sunday, Moscow-backed officials said.
Both Moscow and Kyiv have accused each other of a sharp escalation in attacks on civilian areas in the past two months.
Shattered storefronts and broken glass could be seen in videos shared by Russian state media, along with what appeared to be bodies lying on the ground nearby.
"At the moment, information about 25 dead has been confirmed. At least 20 more people have been injured," said Denis Pushilin, head of the region's Russian-controlled administration.
He blamed Ukraine for the strike, calling it a "horrific" attack on a civilian area.
Ukraine did not immediately comment, and AFP was not able to immediately verify the circumstances of the attack.
Officials said the strike hit a southwestern suburb of the city, less than 15 kilometres (nine miles) from the eastern front.
Local resident Tatiana said she heard an incoming projectile overhead, and hid under her market stall.
"I saw smoke, people screamed, a woman was crying," she told a local media outlet.
"Where is there anything military here? It's just a market," another resident named Tatiana told the same outlet. "This is one of the strongest blows in recent times," she said.
The toll marks one of the deadliest in Donetsk since Moscow launched full-scale hostilities against Ukraine in February 2022.
Donetsk, occupied by Russia and its proxy forces since 2014, has been repeatedly targeted by what Moscow has called indiscriminate Ukrainian shelling.
Moscow called Sunday's attack a "barbaric terrorist attack" that showed the need for its "special military operation" in Ukraine.
"Security threats and acts of terrorism should not be committed from the territory of Ukraine," its foreign ministry said.
News of the attack came as Russia reported another blaze on its energy infrastructure, this time at a gas terminal in the Baltic Sea port of Ust-Luga.
Kyiv earlier this week claimed responsibility for two attacks on oil depots in Russia, including one in the same Leningrad region where Ust-Luga is located.
Operator Novatek said there were no victims and the fire was "currently localised" at the site, some 110 kilometres (70 miles) west of St Petersburg near the Estonian border.
Novatek said the fire was caused by an "external factor", without providing any further detail.
Ukraine, which has targeted Russian oil and gas infrastructure throughout the almost two-year conflict, did not immediately comment on the incident.
"No casualties as a result of a fire at Novatek's terminal in the port of Ust-Luga. Personnel were evacuated," Aleksandr Drozdenko, governor of Leningrad Oblast, said.
He shared a photo showing firefighters spraying water on a large fire at the terminal.
The RIA-Novosti news agency said a 100 cubic metre container was ablaze.
The Ust-Luga complex processes natural gas condensate into naphtha, jet fuel and ship fuel components, according to Novatek's website.