Nine people were killed and seven were injured on Saturday in a Russian drone attack on a bus carrying civilians in northeastern Ukraine, according to local officials.

The strike occurred less than 24 hours after Ukrainian and Russian representatives held their first talks since just after the start of Moscow’s large-scale invasion of Ukraine more than three years ago. During the meeting, which took place in Istanbul, the two sides did not reach a peace deal, but they agreed to exchange 1,000 war prisoners.

The attack occurred near the town of Bilopillia, in Sumy Oblast, a Ukrainian region bordering Russia. Ukrainian police confirmed the strike and released photos of the bus, whose roof was torn off by the explosion.

Oleh Hryhorov, head of the local military administration, announced the death toll. He reported on social media that three of the injured are in serious condition and described the attack as “another war crime by Russia.”

Moscow did not immediately comment on the attack.

On Saturday, Dmitry Peskov, spokesperson for Russian President Vladimir Putin, said that an in-person meeting between the Kremlin leader and Ukrainian President Volodymyr Zelenskyy remains “possible,” but only if certain conditions are met first. Peskov did not specify those conditions, but he commented on the prisoner swap.

“What the delegations agreed to yesterday remains to be done. Of course, it is primarily a question of exchanging 1,000 for 1,000 [prisoners],” he said.

Putin and Zelenskyy have not met since December 2019.