Six people were killed and 12 injured as a truck hit a shuttle bus near the village of Kamyanske, Zaporizhzhya Region.
"We know about six fatalities, five of whom are children. Twelve people were injured," National Police deputy chief Oleksandr Fatsevych said.
There were around 20 people in the shuttle bus.
The 31-year-old driver of the truck, whose braking system may have failed, was detained.