U.S. President Joe Biden's administration has requested Congress to extend the authority of "presidential write-offs" for supplying weapons to Ukraine until 2025, so that the remaining $5.8 billion can be used beyond the fiscal year ending on September 30.
Under current rules, the funds will expire if not used by that deadline.
The Pentagon is working with Congress to ensure the extension, which would allow continued military aid to Ukraine.
If the extension isn't granted, the White House may announce a large aid package by October 1, but this approach could present logistical challenges, such as lack of available resources.
Additionally, U.S. Secretary of State Anthony Blinken recently announced over $700 million in aid to Ukraine during his visit to Kyiv.
The U.S. will provide $325 million to help repair Ukraine's energy infrastructure, which requires strengthening ahead of winter and expectations of a renewed campaign of Russian strikes.
The package also includes $290 million in humanitarian aid, which will support "millions of people in Ukraine and the surrounding region who have been forced to flee their homes," Blinken said.