Zelensky made a plea for air defence, long-range missiles and ammunition in the face of fears that the Hamas attack on Israel could distract key backer the United States from the conflict in his country.

"How to survive during this next winter for us is big," Zelensky 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."

Kyiv's international backers were meeting to discuss arms deliveries, with a focus on keeping Ukraine's counter-offensive advancing and providing air defences to protect against an expected winter onslaught by Russia.

"We will stand by you provide support to Ukraine, because this is really important for the whole of NATO," Stoltenberg told Zelensky.

The Ukrainian president has expressed worries that the crisis in Israel could deflect attention from the war raging in his homeland.

Zelensky urged the West to rally around the Israeli people as it had around Ukraine after Russia's invasion last year, and show them they are not "alone".

"My recommendation to the leaders to go to Israel and I think to support people, just people I'm not speaking about any institutions, just to support people who have been under terrorist attacks," he said.

- 'Underline support' -

The United States has sought to reassure that the decision to step up military support for Israel after the surprise assault by Hamas will not harm Washington's ability to keep arming Ukraine.

The crisis in Israel comes as the White House is scrambling to find a way to keep weapon supplies flowing to Ukraine after turmoil in the US Congress.

Biden has sought 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.

The United States has given as much military support to Ukraine on its own as all European NATO members and Canada combined since Moscow launched its all-out invasion last year.

Western diplomats at NATO insist there is no danger of arms supplies to Ukraine drying up in the near future.

"It's vital to underline our support for Ukraine," Dutch defence minister Kajsa Ollongren said ahead of the talks between Zelensky and his Western supporters in Brussels.

"The war in Ukraine has our attention, and Ukraine has our full support."

Ukraine is pushing to become a member of NATO in a bid to ensure its long-term security in the face of Moscow.

Alliance leaders at a summit this summer simplified Kyiv path for joining, but did not offer a clear invitation or deadline for Ukraine to become a member.