• Odesa regional administration spokesman Serhiy Bratchuk said Soviet-era X-22 missiles were believed to have been used.
• Andriy Yermak, Ukrainian President Volodymyr Zelensky's chief of staff, accused Russia of being a "terrorist country".
At least 21 people, including one child, have died in overnight Russian missile strikes on Ukraine's southern Odesa region, Ukrainian officials say.
The state emergency service, DSNS, says 16 people were killed in a nine-storey building hit by one missile in the village of Serhiyivka.
Another five people, including the child, were killed in a separate strike on a holiday resort in the village.
Russia has fired dozens of missiles on Ukrainian cities in the past few days.
On Friday Kremlin spokesman Dmitry Peskov again denied that Russia was hitting civilian targets.
"We heard three explosions and now there is nothing left of the recreation centre," local resident Yulia Bondar, 60, told the BBC.
"The village is very quiet, we never thought this could happen."
The DSNS said the missiles hit Serhiyivka at about 01:00 on Friday (22:00 GMT Thursday).
It released footage showing firefighters searching for survivors in the wreckage of the nine-storey building.
They were also seen carrying what looked like the body of one of the victims in a bag.
The DSNS says 38 people, including six children, were injured in the Russian strikes.
Maryna Martynenko, a DSNS spokeswoman in the Odesa region, told Ukrainian TV that the building's external wall was damaged, and a nearby shop was set ablaze after the strike. Firefighters later put out the fire.
She said 60 rescuers were currently working at the site.
As many as 150 people are believed to have lived in the building.
The child killed at the holiday resort was a 12-year-old boy, said Kyrylo Tymoshenko, deputy head of President Volodymyr Zelensky's office.
Ukrainian officials said three missiles were launched from Russian warplanes over the Black Sea.
Odesa regional administration spokesman Serhiy Bratchuk said Soviet-era X-22 missiles were believed to have been used.
Andriy Yermak, Ukrainian President Volodymyr Zelensky's chief of staff, accused Russia of being a "terrorist country".
"In response to defeats on the battlefields, they [Russians] are waging a war on civilians," he said.
Ukraine had hoped that the Russian withdrawal on Thursday from the strategically important Snake Island would ease the threat to Ukraine's biggest Black Sea port of Odesa and wider region.
Russia said it had withdrawn its garrison as a "gesture of goodwill" to prove it was not obstructing grain exports from Odesa and other Ukrainian ports - but Ukraine dismissed that claim, saying Moscow continued to shell its grain stores.
In separate developments on Friday:
- Ukraine's military said Russian troops were focusing on encircling Ukrainian soldiers in the eastern city of Lysychansk, aiming "to establish complete control over the Luhansk region"
- The death toll from Monday's Russian missile strike on a busy shopping centre in the central city of Kremenchuk rose to 19, with 62 injured, the DSNS said
- Overnight, Russian troops shelled the Chernihiv, Kharkiv and Mykolaiv regions in Ukraine's north, north-west and south, local officials said