WASHINGTON

US President Donald Trump said Sunday that a Russian missile strike on the Ukrainian city of Sumy that killed over 30 people was "a mistake."

"I think it was terrible. And I was told they made a mistake. But I think it’s a horrible thing," Trump told reporters aboard Air Force One.

"I think the whole war is a horrible thing. I think for that war to have started is an abuse of power. This country would have never allowed that war to have started if I were president. That war is a shame."

It is unclear to whom Trump was referring when he said he was told the strike was a mistake. Asked by reporters to clarify the comment, he said "they made a mistake."

"They made a mistake. I believe it was. Look, you're gonna ask them. This is Biden's war. This is not my war," he said, referring to ex-President Joe Biden. "I’m just trying to get it stopped so that we can save a lot of lives.”

Ukraine said more than 30 people were killed in the strike on the northeastern city of Sumy, located 31 kilometers (19.2 miles) from the Russian border, as people gathered to celebrate Palm Sunday, which starts the Christian celebration of Holy Week.

In two separate statements on X, Ukrainian President Volodymyr Zelenskyy called on the world to "not stay silent or indifferent" to the attacks, saying such strikes deserve "nothing but condemnation."

Zelenskyy also reiterated the need to further pressure Russia as well as to provide Ukraine security guarantees.

He claimed that in the absence of pressure and sufficient support for Ukraine, Moscow will continue to drag out the conflict.

"Unfortunately, there in Moscow they are convinced they can keep killing with impunity. Action is needed to change this situation," he added.

Russian authorities have not immediately commented on the attack or the claims.