Russia said two of its missiles had hit a meeting of Ukrainian military officers on Sunday in the city of Sumy, where Ukraine said Russian strikes had killed 34 people and wounded 117. Russia's defence ministry accused Ukraine of using civilians as human shields by placing military facilities and holding events involving soldiers in the centre of a densely populated city.

Two children were among the scores of people killed in the Palm Sunday strikes on the city’s center, while 117 people were wounded, according to Ukraine’s State Emergency Service.

President Trump late Sunday called a Russian missile strike on a Ukrainian city that left dozens dead a “horrible thing” and said he had been told Russia “made a mistake.”