US President Joe Biden spoke with allies on Tuesday to co-ordinate support for Ukraine after Congress passed a short-term funding bill that left out any new assistance for Kyiv in its continuing fight against the Russian invasion.
White House National Security Council spokesman John Kirby said Mr Biden had held a call with world leaders to discuss joint efforts to continue providing Ukraine with ammunition and weapons systems, including air defence, as they prepare for more Russian attacks on critical infrastructure as winter approaches.
“President Biden made clear that we cannot under any circumstances allow American support for Ukraine to be interrupted,” Mr Kirby told reporters.
“Time is not our friend – we have funding authorities to meet Ukraine's battlefield needs for a bit longer, but we need Congress to act to ensure that there is no disruption in our support.”
Canadian Prime Minister Justin Trudeau as well as the leaders of Germany, Britain, Italy, Poland, Japan, Romania, Nato, the European Commission and the European Council were on the call, according to Mr Kirby.
The call came after Congress passed a last-minute stopgap bill on Saturday that will keep the US government running until November 17, but did not authorise any new Ukraine assistance.
The development came as the right wing of the Republican Party increasingly calls for broad cuts to US spending, including Ukraine aid.
Since Russia launched a full-scale invasion of Ukraine in February last year, the US has approved about $113 billion in military and humanitarian aid.
Mr Biden has approved several military packages that have included a wide range of weapons systems including tanks and artillery, which are vital to Ukraine's battlefield efforts.
Mr Kirby said world leaders on the call understood it was only a minority of Republicans who are opposing additional aid to Ukraine.
“We know that the world is watching,” Mr Kirby said.
“So the President looks forward to working with Congress to ensure that we make good on our commitments.”
Pentagon spokeswoman Sabrina Singh said the Defence Department had $1.6 billion left to replace weapons sent to Ukraine, no funds left under the Ukraine Security Assistance Initiative and $5.4 billion of Presidential Drawdown Authority, which allows Mr Biden to utilise defence stocks.
“We have enough funding authorities to meet Ukraine's battlefield needs for just a little bit longer, but we need Congress to act,” Ms Singh said.
Existing funds would last Ukraine “perhaps a couple of months”, Mr Kirby said.
“Given what we have left and the pace at which we have been providing support, you're talking perhaps a couple of months or so – depends what's going on the battlefield,” he said.
Mr Biden has urged Republicans in Congress to back a bill that would provide $24 billion in aid to Ukraine and has sought to reassure world leaders that there was still “overwhelming” bipartisan support on the issue.
Mr Kirby said that US leadership remains “key” to ensuring that international support for Ukraine continues.