Trump reacted to Russia’s strike on Sumy: It was horrible. I was told Russians had made mistake

US President Donald Trump has called the Russian strike on Sumy on 13 April "horrible".
According to Censor.NET, this was reported by "Radio Liberty"
"I think it was terrible. And I was told that they had made a mistake. But I think it was terrible. I think the whole war is terrible," Trump told reporters on board Air Force One.
At the same time, the US president, who is promoting the idea of a ceasefire in Russia's war against Ukraine, did not specify what he meant by the words "made a mistake".
As a reminder, on 13 April, Russian invaders launched two missile strikes on the centre of Sumy. The attack killed 34 people, including two children. Also, 117 people were injured, including 15 children.