A Russian ballistic missile attack hit a residential area in Ukraine's Black Sea port city of Odesa on Friday, killing at least 20 people and wounding more than 70, in Moscow's deadliest attack in weeks, Ukrainian officials said.
President Volodymyr Zelenskiy said Russia would receive a "fair response" from Ukrainian forces for what he said was a "vile" strike on a city that has been attacked by Russian drones or missiles almost every day this month.
Two Iskander-M missiles fired from the Russian-occupied Crimea peninsula damaged civilian infrastructure and gas and electricity supply lines in the southern city, regional governor Oleh Kiper said on national television.
Some residents were facing gas and electricity supply cuts as a result of strikes, he added.
"The explosion was very strong, especially the second one... This is a very powerful missile that flies from the occupied Crimea in a few minutes," Kiper said.
A medic and rescuer were killed by a second missile after rushing to the scene to treat people hurt in the initial strike. Ten people had suffered serious injuries, Kiper added.
"Our Defense Forces will certainly do everything to ensure that the Russian killers feel our fair response," Zelenskiy said on Telegram.
Residents were rushing to donate blood, creating queues at medical centers. Saturday was declared a local day of mourning.
A three-storey recreational facility was destroyed in the attack as well as at least 10 private houses, the southern military command said.
Bodies were laid out in foil protective blankets, while dozens of rescuers battled to put out fires and continued clearing the rubble.
Odesa, one of Ukraine's biggest ports, has long been a target of Russian attacks, especially after Moscow quit a UN-brokered deal that had allowed safe passage for Ukrainian grain shipments via the Black Sea.
"The Russian terror in Odesa is a sign of the weakness of the enemy, which is fighting against Ukrainian civilians at a time when it cannot guarantee the safety of people on its own territory," Ukrainian presidential chief of staff Andriy Yermak wrote on Telegram.
Moscow denies targeting civilians in the full-scale invasion of Ukraine which it launched in February 2022, although many have been killed in frequent Russian air strikes across the country.
Ukraine has developed and used long-range drones to try to strike back at Russia, stepping up attacks on a string of oil refineries this week in the run-up to Russia's March 15-17 presidential election.
Ukraine attacked a small refinery in Russia's Kaluga region with drones early on Friday in an operation that was conducted by the GUR military spy agency, a Ukrainian intelligence source told Reuters.
