The White House budget chief warned the US Congress on Monday that failure to agree fresh funds for Ukraine by the end of the year would "kneecap" Kyiv on the battlefield.
In a letter to the House Speaker, the director of the Office of Management and Budget Shalanda Young said time was rapidly running out to support Ukraine's fight against the Russian invasion.
"I want to be clear: without congressional action, by the end of the year we will run out of resources to procure more weapons and equipment for Ukraine," Shalanda Young wrote.
"Cutting off the flow of US weapons and equipment will kneecap Ukraine on the battlefield," she added.
President Joe Biden asked Congress in October to approve $106 billion in national security funding, including support for Ukraine and for Israel's war against Hamas.
But Congress has been paralyzed for months by Republican infighting, with hard-right lawmakers particularly opposing any further assistance for Kyiv as the war drags on.
New Republican House Speaker Mike Johnson, a little-known ally of former president Donald Trump, took office in October after his predecessor Kevin McCarthy was ousted by a right-wing coup.
Under Johnson, Congress narrowly averted a chaotic government shutdown over the Thanksgiving holiday in November, but the deal to keep the lights on until mid-January left out aid to America's key allies.
- 'Out of money' -
The strongly worded letter from the White House's budget director said that by that time it would be too late and funds for Ukraine would have already dried up.
"There is no magical pot of funding available to meet this moment. We are out of money -- and nearly out of time," Shalanda Young wrote.
She said failure to agree more funding was not only putting Ukraine's gains to date at risk, but increasing the chance of Russian military victories.
"This isn't a next year problem. The time to help a democratic Ukraine fight against Russian aggression is right now. It is time for Congress to act," she wrote.
Ukraine has been desperately pushing for more foreign aid as Russian forces step up attacks in the east after holding back Kyiv's much-vaunted counteroffensive.
As the war enters a third winter, the frontline has largely remained static for the last year despite a massive push by Ukrainian forces this summer with Western military hardware.
Casting Russian President Vladimir Putin and Hamas as twin forces trying to "annihilate" neighboring democracies, Biden has sought to tie $61 billion for Ukraine with $14 billion for Israel in the aid package he demanded in October.
The United States has already provided $40 billion in security aid to Ukraine since Russia invaded in February 2022.
Ukraine also threatens to weigh on Biden's reelection chances as the Democrat seeks a second term, with polls showing a growing number of voters saying the United States is doing too much to help Kyiv.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)