He will also meet German Chancellor Olaf Scholz and then head to Italy, following the meeting at Ramstein Air Base, which comes days after 55 people were killed and 300 wounded in a Russian missile strike on the city of Poltava.

"We need more weapons to drive Russian forces off our land," Zelensky said.

He also urged Kyiv's supporters to follow through on previous commitments, saying: "The number of air defence systems that have not been delivered is significant."

And he again called for restrictions on the use of long-range Western weapons to hit targets inside Russia to be lifted.

"We need to have this long-range capability, not only on the occupied territory of Ukraine, but also on the Russian territory," Zelensky said.

The meeting at the base southwest of Frankfurt is being hosted by US defence chief Lloyd Austin, who announced that Washington will provide $250 million in new military aid for Ukraine.

The package "will surge in more capabilities to meet Ukraine's evolving requirements," Austin told the meeting.

The assistance is expected to include ammunition for HIMARS precision rocket launchers, artillery rounds, anti-tank and anti-air weapons, a US defence official said on condition of anonymity.

The talks in Germany, with representatives from some 50 nations, will focus on areas including bolstering Ukraine's air defences and encouraging allies to boost their defence industries, Pentagon spokesman Major General Pat Ryder said ahead of the meeting.

"Ukraine matters to US and international security, and the efforts of (Kyiv's allies meeting in Ramstein) continue to play a vital role in Ukraine's fight for freedom and sovereignty," he said.

The meeting comes as Moscow's forces advance in the Donbas, with Russian President Vladimir Putin on Thursday declaring that capturing the eastern area was his "primary objective" in the conflict.

Since the start of its offensive in February 2022 when it failed to seize the Ukrainian capital Kyiv, Russia has adapted its aims, concentrating instead on trying to conquer eastern Ukraine.

- Uncertainty over Ukraine backing -

While Ukraine's surprise push into Russia's Kursk region last month caught Russian forces off-guard, Putin stressed that the move had failed to slow Moscow's advance.

"The enemy weakened itself in key areas, our army has accelerated its offensive operations," Putin argued.

Ukraine on Friday claimed to have recaptured a part of the eastern Ukrainian town of New York, in the first success for Kyiv on this part of the front for months.

"Thanks to the high morale, courage and professionalism of the brigade's fighters, Azov managed to stabilise the situation, regain control of part of New York," the Azov Brigade, fighting in the area, said on social media.

The United States has been Ukraine's biggest backer during the conflict, providing military aid worth more than $56 billion (50 billion euros), according to the Pentagon.

But uncertainty looms over the future of that funding as a US election in November could see Ukraine-sceptic Donald Trump back in the White House.

Germany, Ukraine's second-biggest backer, has also come under pressure domestically over its aid for Kyiv, which has been at the centre of a protracted row over the 2025 budget.

Regional elections in the former East German states of Saxony and Thuringia on Sunday saw a surge of support for parties on the far right and far left opposed to the government's support for Ukraine.

France, another of Kyiv's biggest backers, has also been locked in a political crisis for several weeks.

Ahead of the meeting, Britain said it would send Kyiv 650 lightweight missiles before the end of the year to boost Ukraine's air defence capabilities.

Meanwhile, Ukraine's allies in Europe have moved to expand their own defences in response to the increased threat from Russia.

Germany's military put a first Iris-T air-defence system into service on its own soil Wednesday, having delivered several of them to Ukraine to intercept Russian rockets, drones and missiles.