Ukrainian President Volodymyr Zelenskyy has issued a plea for allies to increase weapons donations to help his troops battle the Russian army through the winter.
During his first visit to Nato’s headquarters since Russia invaded his country, Mr Zelenskyy called on the military alliance to send air defence, long-range missiles and ammunition as the colder months approach.
His appeal came amid fears the Hamas attack on Israel could distract the US from the conflict raging in eastern Europe.
The Ukrainian President said his army is braced for fighting throughout the winter months.
“How to survive during this next winter for us is big,” he said as he addressed the media with Nato chief Jens Stoltenberg before meeting alliance defence ministers.
“We are preparing, we are ready. Now we need some support from the leaders. That's why I'm here today.”
The US is a key backer of Mr Zelenskyy’s government and has provided about $44 billion in security assistance to Ukraine since the beginning of Russia's invasion in February 2022.
Washington has given as much military support to Ukraine on its own as all European Nato members and Canada combined.
The government is providing a further $200 million in additional military aid for Ukraine in a package expected as soon as Wednesday, US officials have said.
US Defence Secretary Lloyd Austin said the package would include air defence missiles to help Ukraine stave off an expected winter onslaught by Russia.
“Make no mistake,” Mr Austin said at the start of the meeting with Ukraine's international backers.
“The United States will stand with Ukraine for as long as it takes.”
The latest arms package from Washington is the first announced since turmoil in the US Congress cast doubt on the ability of President Joe Biden to maintain support.
The Ukrainian President has more recently expressed worries that the war between Israel and Hamas could deflect attention from Russia’s invasion of its neighbour.
As Ukraine approaches the grim milestone of 600 days of war, Mr Zelenskyy urged the West to rally around the Israeli people as Kyiv's backers did for Ukraine after Russia's invasion last year, and show them they are not “alone”.
He underscored the importance of air defences to protect Ukraine's civilian infrastructure as the country gears up for a repeat of Moscow's bombing campaign last winter.
“Dear friends, we must win the winter battle against terror,” he told Kyiv's backers.
The Biden administration has sought to reassure the Ukrainians that the decision to expand military support for Israel will not harm its ability to keep arming Ukraine.
After Hamas launched a large-scale attack on Israel on Saturday, the US has joined allies to pledge full support for the Israelis.
The US Navy has sent the USS Gerald R Ford carrier strike group to the waters near Israel in a show of support for its ally.
Antony Blinken, the US Secretary of State, is expected to visit Israel later on Wednesday follow what has been described as the country’s “9/11 moment”.
Israeli Defence Minister Yoav Gallant was set to brief his Nato counterparts by video-link on Thursday.
The crisis in Israel comes as the White House is scrambling to find a way to keep weapon supplies flowing to Ukraine after difficulties in the US Congress.
President Biden has tried to calm nerves among allies over Washington's backing for Kyiv after new assistance was dropped from a deal in the US Congress to avoid a government shutdown this month.
Western diplomats at Nato insist there is no danger of arms supplies to Ukraine drying up in the near future.
Nato Secretary General Jens Stoltenberg said the transatlantic alliance “must continue to step up and sustain the steady flow, of weapons and ammunition to Ukraine.”