On Saturday, US Defense Secretary Lloyd Austin demanded Congress not to delay in passing the full-year spending bill, known as an omnibus, stressing it was key to helping keep the United States secure.

"Let me urge Congress to pass an on-time appropriation so that we can get the capabilities to further strengthen our deterrence," Austin told the Reagan National Defense Forum in Simi Valley, California, which was attended by Republican and Democratic lawmakers.

A commonly floated alternative to an omnibus, known as a continuing resolution, would effectively freeze spending at current levels. Such a bill would call the armed forces for relying on legacy equipment while developing new military technologies would largely stop, US lawmakers have warned.

It is worth mentioning that the US Senate approved in September $12 billion in fresh economic and military aid for Ukraine as part of Washington's stopgap extension of the US federal budget into December.

The bill, met with bipartisan support, includes $3 billion for arms, supplies, and salaries for the Ukrainian military while authorizing US President Joe Biden to direct the Department of Defense to provide Ukraine with $3.7 billion of its own weapons and materiel using his Presidential Drawdown Authority.

The act further provides $4.5 billion for Kiev to stabilize the country's finances and keep Kiev's government afloat.

Since the start of the war, the US has given Ukraine $16.9 billion for "security assistance", which includes a package worth $600 million in early September. Additionally, the White House asked Congress for $13.7 billion for "security and economic assistance" for Ukraine, which the body must pass by the end of the month to keep the Ukrainian government standing.

Aid to Kiev is part of a short-term extension of the federal budget that expires at the end of the fiscal year without Congress agreeing to a full-year allocation for fiscal 2022-23.