President Joe Biden has asked Congress to approve a $33 billion aid package that will provide Ukraine’s government with “critical security, economic and humanitarian assistance” at what he called “a very pivotal moment,” as Russian President Vladimir Putin’s forces step up attacks in the southern and eastern regions of the country.

“We can’t stand by as the Russians continue their atrocities and aggression in Ukraine. Every day the Ukrainians are paying with their lives for this fight, and we need to contribute arms, funding, ammunition and the economic support to make their courage and sacrifice have purpose so they can continue this fight and do what they're doing,” Mr Biden said, adding that it is “critical” for Congress to approve the package “as quickly as possible”.

The supplemental request will augment the $14 billion allocated in the Fiscal Year 2022 budget Mr Biden signed into law on 15 March, which an administration official said has allowed the United States to “respond to Russia’s aggression in Ukraine at “a scope, scale and speed that has never been seen before” by helping Ukraine “win the battle of Kyiv and continue to deplete the Russian military”.

But because Russia’s war against Ukraine could last for what an official said could be “months or more,” Mr Biden will tell Congress that more assistance is necessary.

A senior administration official said the $33 billion request represents “what we believe is needed to enable Ukraine’s success over the next five months of this war”.

Additionally, the $33 billion supplemental request will provide funds to enable the US to replenish weapons stockpiles that have been drawn down for shipment to Ukraine’s armed forces, and will help US allies “shift away from their dependence on Russian weapons”.

Specifically, the bill would provide $20.4 billion in direct security and military assistance, as well as funds for US efforts “to strengthen European security” in cooperation with Nato allies, including “$5 billion in additional drawdown authority, $6 billion for the Ukraine Security Assistance Initiative, and $4 billion for the State Department’s Foreign Military Financing program.

The appropriations package will also provide $8.5 billion in financial assistance to Ukraine’s government to allow it to “continue performing basic functions, address food insecurity exacerbated by Russia’s war of aggression, and support Ukrainian refugees and the countries that are providing them sanctuary”.

Mr Biden said previous rounds of US assistance has allowed the US and Nato allies to facilitate “a significant flow of weapons and systems Ukraine ... including tanks, artillery and other weapons,” and stressed that support to Kyiv is being delivered “with unprecedented speed”.

“Much of the new equipment we've announced in the past two months ... has already gotten to Ukraine where it can be put to their direct use on the battlefield,” he said, but the funds already authorised for assistance to Kyiv has been exhausted, which requires Congress to take action once more.

“Basically, we're out of money, and so that's why today — in order to sustain Ukraine as as it continues to fight — I'm sending Congress a supplemental budget request. It's going to keep weapons and ammunition flowing without interruption to the brave Ukrainian fighters, and continue delivering economic and humanitarian assistance to the Ukrainian people,” he said.

“This assistance would provide even more artillery, armored vehicles anti-armour systems, [and] anti-air capabilities that have been used effectively thus far in the battlefield by the Ukrainian warriors,” he continued, adding that the package would also “deliver much needed humanitarian assistance as well as food water, medicine, shelter, and other aid to Ukraine is displaced by Russia's war and provide aid for those seeking refuge in other countries from Ukraine”.

“It's also going to help schools and hospitals open which can allow pensions and social support to be paid to the Ukrainian people so they have something something in their pocket. It's also going to provide critical resources to address food shortages around the globe,” Mr Biden said.

Mr Biden said he is also asking Congress for a “comprehensive legislative package” that will make it easier for US officials to seize assets belonging to Russian oligarchs and transfer seized assets to Ukraine.

“We're going to seize their yachts, their luxury homes and their other ill-begotten gains of Putin's kleptocracy,” he explained. “This legislative package transfers all law enforcement capabilities to seize property linked to Russia's kleptocracy —it’s going to create new expedited procedures for forfeiture and seizure of these these properties. That's going to ensure that when they oligarchies assets are sold off, funds can be used directly to remedy the harm Russia caused in our help and help rebuild Ukraine”.

Mr Biden added that all the actions his administration is taking are about “the truth” that “investing in Ukraine’s freedom and security is a small price to pay to punish Russian aggression, to lessen the risk of future conflicts”.

“Throughout our history, we learned when dictators do not pay the price for their aggression, they cause more chaos and more aggression, and they keep moving, and the costs of threats to America and the world keep rising. We can’t let this happen,” he said. “Our unity at home, and our unity with our allies and partners, and our unity with the Ukrainian people is sending an unmistakable message to Putin: You will never succeed in dominating Ukraine”.