Ukrainian President Volodymyr Zelenskyy refuted President Donald Trump's characterization of the war between Russia and Ukraine when he likened the countries to "two young people fighting like crazy" and saying "sometimes you're better off letting them fight for a while."

In an exclusive interview airing Sunday on "This Week with George Stephanopoulos," co-anchor Martha Raddatz asked Zelenskyy if Trump "is getting the message" of suffering in Ukraine based on his Oval Office remarks.

"We are not kids with Putin at the playground in the park," Zelenskyy said Friday. "He is a murderer who came to this park to kill the kids."

Zelenskyy described the "limitless" pain of a Ukrainian father who lost his wife and three children in a missile strike.

The man's words to Zelenskyy were "different" than how officials talk about loss, the Ukrainian leader said.

"He wasn't mentioning any statistics or figures and numbers of strikes."

"He just said, 'Every morning when I wake up, I'm just looking for my family -- I'm looking everywhere in the flat ... I still feel that it was a nightmare … a bad dream,'" Zelenskyy said the man told him.

Trump "could not feel fully and understand this pain," Zelenskyy said.

"And it's not about President Trump, it's about any person who is not here in the country, who is some thousands of miles away -- [they] cannot feel fully and understand this pain," he said.

The Ukrainian president told Raddatz that 631 Ukrainian children have died in the war, and that Russia often targets civilians in its offensive.

In a recent study, the Center for Strategic and International Studies estimated between 60,000 and 100,000 Ukrainian soldiers have died in the war, and as many as 250,000 Russian troops have died from the fighting.