President Trump on Tuesday threatened to cancel an upcoming meeting with Russian President Vladimir Putin after the nation fired at Ukrainian naval vessels and seized multiple ships and their crews over the weekend.

"Maybe I won't have the meeting," Trump said, according to The Washington Post. "Maybe I won’t even have the meeting . . . I don’t like that aggression. I don’t want that aggression at all.”

UKRAINIAN PARLIAMENT VOTES TO IMPOSE MARTIAL LAW AFTER RUSSIA ALLEGEDLY SEIZED COUNTRY'S SHIPS

The president's remarks come after relations between Russia and Ukraine intensified on Sunday, when Russian border guards fired upon three Ukrainian ships and captured 24 of their men as they were sailing through the Kerch Strait, near Crimea, which is the only outlet for Ukrainian vessels to the Black Sea.

Trump said he was waiting for a "full report" from his national security advisers later Tuesday about the alleged attack, claiming the information would be "very determinative."

On Monday, the president said the U.S. did not approve of escalating violence between Russia and Ukraine, but didn't specifically call out Russia's behavior.

"We do not like what's happening, either way, we don't like what's happening and hopefully it will get straightened out," he said, hours after U.S. Ambassador to the United Nations Nikki Haley condemned Russia for their "outrageous violation of sovereign Ukrainian territory" that marked "yet another reckless Russian escalation."

Trump and Putin — who were originally slated to meet in Paris earlier this month — are scheduled to meet at the G20 Buenos Aires summit in Argentina later this week.