A devastating Russian attack against Ukraine on Palm Sunday, coming days after Russian President Vladimir Putin shook hands with President Trump’s top negotiator, is raising doubt about the U.S.’s strategy in ceasefire talks with Moscow.

Russian missiles hit the heart of the Ukrainian city of Sumy as people gathered to celebrate Palm Sunday, killing at least 34 people, officials said, in the second large-scale attack to claim civilian lives in just over a week.

Russia hit the Ukrainian city of Sumy with two missiles as civilian celebrated Palm Sunday, killing more than 30 people and injuring dozens of others, officials said.