Russian missiles struck the Ukrainian city of Vinnytsia far behind the frontlines in an attack which Ukrainian officials called a war crime and said had killed at least 23 people, including three children.
The strike, which Ukraine said had been carried out with Kalibr cruise missiles launched from a Russian submarine in the Black Sea, came a day after a breakthrough in talks between Moscow and Kyiv to unblock Ukrainian grain exports and underscored how far the two sides remain from a peace settlement.
"What is this, if not an open act of terrorism?" Ukrainian President Volodymyr Zelensky wrote on the Telegram messaging app.
Deputy UN spokesman Farhan Haq said UN Secretary-General Antonio Guterres is "appalled" by the missile attack and added, "the Secretary-General condemns any attacks against civilians or civilian infrastructure and reiterates his call for accountability for such violations."
The Russian defence ministry, which denies deliberately targeting civilians, did not immediately comment on the strike.
Ukraine's state emergency service said on its Facebook page that 23 people including three children had been killed, with 66 hospitalized and 39 others still missing.
Zelensky told an international conference aimed at prosecuting war crimes in Ukraine that the attack had been mounted on "an ordinary, peaceful city".
"Cruise missiles hit two community facilities, houses were destroyed, a medical centre was destroyed, cars and trams were on fire," he said.
Ukraine interior minister Denys Monastyrskyi said later two more missiles had been intercepted en route by air defences.
Russia, which launched what it called its "special military operation" against Ukraine on 24 Febraury, says it uses high-precision weapons to degrade Ukraine's military infrastructure to protect its own security.
Vinnytsia, a city of 370,000 people about 200km southwest of the Ukrainian capital Kyiv, hosts the command headquarters of the Ukrainian Air Force, according to an official Ukrainian military website, a target which Russia used cruise missiles to try to hit in March, the Ukrainian air force said at the time.
Video footage showed thick black smoke billowing out of a tall building, while photographs posted online by the State Emergency Service showed grey smoke rising later from the twisted remains of burnt-out cars and smouldering rubble.
One showed an abandoned, overturned pram lying on the street.
In comments on Twitter, Foreign Minister Dmytro Kuleba accused Russia of committing "another war crime".
"This is terrorism. Deliberate murder of civilians to spread fear. Russia is a terrorist state and must be legally recognised as such," Kuleba wrote.
The United States and more 40 other countries agreed on Thursday to coordinate investigations into suspected Russian war crimes in Ukraine.
Russia denies the accusations, and Dmitry Medvedev, a former president who is now deputy chairman of Russia's Security Council, has said that attempts by the West to punish a nuclear power such as Russia for the conflict in Ukraine risk endangering humanity.
The Kremlin has said that Russia is ready to halt what the West calls Moscow's unprovoked war of aggression if Kyiv agrees to its conditions.
Russian Deputy Foreign Minister Andrey Rudenko said on Thursday that Moscow would respond positively should Kyiv be ready to resume peace negotiations, the Interfax news agency reported. Kyiv would have to affirm its non-aligned and non-nuclear status and formally recognise existing territorial realities, Rudenko was cited as saying.
Specifically, he said that would mean recognising that Crimea, annexed by Moscow in 2014, was under Russian control, and that two self-proclaimed Russian-backed statelets in eastern Ukraine were no longer under Kyiv's remit.
Separately, the top Russian-installed official in a region of southern Ukraine partly under Moscow's control said on Thursday it would hold a referendum in early autumn on whether to become part of Russia.
Ukraine has repeatedly said it is unwilling to concede any territory to a country it calls a hostile occupier and has said it plans to take back any land lost by force.
- Reuters