It is the third Russian attack on a Ukrainian training unit in little more than two months. An Iskander missile attack on a camp in the norther border region of Sumy killed six servicemen in May and another strike killed 12 people and wounded another 60 last month.

Sixteen of the people were killed when Russia bombed a prison in the frontline Zaporizhzhia region in an attack Ukrainian President Volodymyr Zelenskiy said was deliberate.

The attack, just hours after President Trump gave the Kremlin a new deadline to work toward ending the war, was part of a wave across the country, the authorities said.