Trump also slammed Zelensky for suggesting that the end of Russia's war against Ukraine likely "is still very, very far away."

For days Trump cabinet officials have suggested Ukraine’s President Volodymyr Zelensky might need to step aside. Yet Ukrainian officials and analysts told CNN any change of president in Kyiv would spark at least six months of political limbo,

The order, which takes effect immediately, affects more than $1 billion in arms and ammunition in the pipelines and on order.

Sky News reporter Yalda Hakim asked Ukraine President Zelensky at an event with British reporters Sunday (full replay here) to respond to Sen. Lindsey Graham's comment that Zelensky might have to resign in order for Trump to make a deal with Ukraine and Russia.

The Oklahoma senator said if Ukrainian President Volodymyr Zelensky were removed, that would "spiral Ukraine into chaos."