"Russia, frankly, has been fine on Ukraine. They haven't been doing much," Trump said, hours after a Russian drone strike in a public park killed six people, including two children.

The conversation with Zelensky comes three days after the pope spoke with Russian President Vladimir Putin to call for a ceasefire to evacuate civilians from the front-line town.

Three military personnel and three personnel were injured and are receiving treatment. The gunman has been detained and investigation is underway.

"His country is in shambles, a large portion of his land is lost, his oceans and seas are gone, and his male population is low, wounded, and/or dead."