The top general for US forces in Europe has told Congress that Ukraine will be outgunned 10 to one by Russia within a matter of weeks if Congress does not find a way to approve sending more ammunition and weapons to Kyiv soon.

The evidence from Army General Christopher Cavoli, head of US European Command, and Celeste Wallander, assistant secretary of defence for international security affairs, comes as Congress enters pivotal weeks for voting for aid for Ukraine, but there is no guarantee funding will be approved in time.

Ukraine has been rationing its munitions as Congress has delayed passing its 60 billion dollar (£48 billion) supplemental Bill.

“They are now being outshot by the Russian side five to one. So the Russians fire five times as many artillery shells at the Ukrainians than the Ukrainians are able to fire back. That will immediately go to 10 to one in a matter of weeks,” Gen Cavoli said.

“We’re not talking about months. We’re not talking hypothetically.”

Republican House Speaker Mike Johnson has been trying to find a way forward for the Bill that would fund new rounds of munitions production at US firms to enable the Pentagon to then rush more munitions to Ukraine.

Mr Johnson is trying to bring it to the floor for a House vote, but he is facing concerns from members who cite domestic needs, including border security.

The speaker is also facing a threat to his leadership role from his far-right flank by Georgia Republican Representative Marjorie Taylor Greene, who has called for his ousting over the issue.

While the political battles on Capitol Hill continue, the dire battlefield situation in Ukraine worsens.

Gen Cavoli told the legislators that in this conflict the US flow of 155mm artillery shells has been a lifeline.

“The biggest killer on the battlefield is artillery. In most conflicts, but in this one definitely. And should Ukraine run out, they would run out because we stopped supplying – because we supply the lion’s share of that,” Gen Cavoli said.

Russia’s own production of missiles has ramped up and can launch large-scale attacks every few days.

If Ukraine’s air defence stocks run out, “those attacks would absolutely cripple the economy, and the civil society as well as the military of Ukraine if they were not defended against without a US provision of interceptors,” Gen Cavoli said.

“Their ability to defend their terrain that they currently hold and their airspace would fade rapidly, will fade rapidly without the supplemental,” Gen Cavoli said.

If Kyiv falls, it could imperil Ukraine’s Baltic Nato member neighbours and potentially drag US troops into a prolonged European war.

At a Capitol Hill press conference on Wednesday, Mr Johnson said: “House members are continuing to actively discuss our options on a path forward.”

“It’s a very complicated matter at a very complicated time. The clock is ticking on it, and everyone here feels the urgency of that, but what’s required is that you reach consensus on it, and that’s what we’re working on,” Mr Johnson said.

Michigan Democrat Representative Elissa Slotkin urged a vote.

“Speaker Johnson has a choice to make. I accept that it’s a complicated choice. I accept that he’s at risk of losing his job over that choice,” Ms Slotkin said.