The US is “running out of time to help them,” Burns said during an event at the George W. Bush Presidential Center in Dallas, characterizing a scenario in which Congress doesn’t approve billions of dollars in supplemental assistance to Ukraine as “dire.”

There is a very real risk that the Ukrainians could lose on the battlefield by the end of 2024, or at least put Putin in a position where he could essentially dictate the terms of a political settlement,” Burns said.

The CIA director explained that Ukrainian forces are not lacking will but “running out of ammunition” at an alarming rate.

He noted that in the days before the fall of the eastern town of Avdiivka in February, Ukrainian brigades – 2,000 members strong – were limited to firing only 15 artillery rounds and 42 mortar shells per day.

“They were overwhelmed,” Burns said, predicting “more Avdiivkas in the future” without supplemental US assistance.

The House of Representatives is expected to vote on four foreign aid bills Saturday, including a $60.8 billion package for Ukraine.

“With the boost that would come from military assistance, both practically and psychologically, Ukrainians are entirely capable of holding their own through 2024 and puncturing Putin’s arrogant view that time is on his side,” Burns said.

More firepower would allow the Ukrainian military to conduct “deeper strikes” against targets in Crimea and Russia’s Black Sea Fleet, according to the CIA director.

Burns also echoed the concerns of European leaders and some US lawmakers that Russian President Vladimir Putin will attempt to seize territory beyond Ukraine if he prevails in the former Soviet state.

“I don’t think his ambitions would stop there,” he said.