Senator John McCain (R-AZ) on Wednesday referred to North Korean leader Kim Jong-Un as a “crazy fat kid”.

“China is the one, the only one, that can control Kim Jong-Un, this crazy fat kid that’s running North Korea,” he told MSNBC’s Greta Van Susteren.

“They’re the ones. They could stop North Korea’s economy in a week,” added McCain, who compared Kim to Soviet Union leader Joseph Stalin.

“He’s not rational, Greta. We’re not dealing even with someone like Joseph Stalin, who had a certain rationality to his barbarity,” he said.

McCain’s comments followed North Korea’s latest acts of aggression, as it tested a powerful new rocket engine earlier this week, hailed by Kim as a "new birth" for the nation's rocket industry.

Earlier this month, North Korea fired four ballistic missiles into the sea off Japan's northwest coast.

McCain has previously called for a more aggressive stance on North Korea in United States policy. In January 2016, he said America should deploy a missile system in the Korean Peninsula in response to North Korean claims it conducted a nuclear test.

Reports this week said the Trump administration was considering imposing sanctions aimed at cutting North Korea off from the global financial system.

On Tuesday, a North Korean official made clear his country would continue the "acceleration" of its nuclear and missile programs despite the United States’ threats to impose sanctions on it.