Andreas Arnold/picture alliance/Getty Images
Zelensky (right) with US Secretary of Defense Lloyd Austin at the Friday meeting.
Ramstein Air Base, Germany CNN  — 

Ukrainian President Volodymyr Zelensky urged international allies on Friday to speed up deliveries of promised air defenses, warning of a “significant” shortfall in vital aid.

Speaking at Ramstein Air Base in Germany at the opening of the 24th Ukraine Defense Contact Group meeting, Zelensky said the weapons systems were essential to hold back Russian forces.

“I will not speak openly now about the number of systems they have received — thank you so much again — but the number of air defense systems that have not yet been delivered is significant,” Zelensky said.

“This is what was agreed upon, and this is what has not been fully implemented. The world has enough air defense systems to ensure that Russian terror does not have results, and I urge you to be more active in this war with us in air defense.”

US Defense Secretary Lloyd Austin, speaking alongside Zelensky, said the Biden administration would announce another $250 million security assistance package for Ukraine. Since the Ukraine Defense Contact Group (UDCG) meeting in June, he said, the US has committed more than $4 billion in new security assistance for Kyiv.

Among the capabilities expected to be included in the aid package are 155mm and 105mm artillery rounds, ammunition for High Mobility Artillery Rocket Systems (HIMARS), anti-tank and anti-aircraft weapons, and spare equipment parts, according to a defense official.

But Austin continued to resist Ukraine’s calls for approval to use long-range strike capability within Russia, telling reporters later on Friday that that there was “no one capability” that would be a game changer on the battlefield.

The UDCG have met regularly since Russia’s invasion of Ukraine in February 2022, but Zelensky’s in-person appearance added extra relevance to the latest gathering.

Austin said Zelensky and the Ukrainian people had “inspired the world.”

Friday’s meeting comes amid an increased push by Ukrainian leaders for the loosening of restrictions to use long-range weapons inside Russia. A week ago, Ukrainian Defense Minister Rustem Umerov presented a list of targets inside Russia to the Biden administration during a visit to Washington. Days later, Russia launched one of the deadliest single attacks since the beginning of the war, killing dozens of people and injuring more than 200 more in a strike on a military educational facility in central Ukraine.

Last month Zelensky said he would be attending the United Nations General Assembly in September, where he would meet President Joe Biden. He added that the success of his so-called “plan for victory” largely depends on the US.

But Austin said he did not discuss that plan with Zelensky when they spoke at Friday’s meeting. “We talked about a number of things, but that specific piece we didn’t discuss,” he told reporters.

Canadian Minister of National Defense Bill Blair said Friday that his country supports Ukraine’s request to use long-range weapons on military targets inside Russia.

“One of the things that President Zelensky and his ministers have made very clear to us is that they are suffering significant attacks from airbases and military installations located within Russia, that those attacks are aimed towards their cities, their citizenry, and their critical infrastructure,” Blair said.

“And in order to properly defend themselves they have asked for permission to use long range fire capabilities that are being provided by the UDCG… I believe very sincerely that that will enable them to do a better job of protecting themselves.”

And while the US has said that much of the high-value targets inside Russia, such as the aircraft launching glide bombs, are outside of the range of long-range weapons like ATACMS — which have been a primary request from Ukraine — Blair said Russia moving capabilities out of that range is a win in itself.

“By moving them [glide bombs] further back, it’s made them less effective and has decreased the vulnerability of Ukraine’s cities and critical infrastructure,” he said. “And so if the Russians are being responsive to that potential threat, then I think that could be a very positive thing as well if it makes the Ukrainians’ situation more defensible and safer.”

Lithuanian Defense Minister Laurynas Kasčiūnas also said that Lithuania supports the lifting of restrictions on long-range strike capabilities, and added that “many” other countries do as well, though he didn’t name them. He blamed “Russian propaganda” for concerns about escalating the fight in Russia if Ukraine were to get the approval to strike military targets in the country.

“They are using it as a deterrence for more support to Ukraine, so I would recommend not to be convinced by this Russian propaganda and to do what we need to do to support Ukraine as much as possible,” he said.

Austin noted that Kyiv was continuing to “seize the initiative on the battlefield,” a clear reference to Ukraine’s ongoing offensive in Russia’s Kursk region.

“The Kremlin’s army of aggression is now on the defensive on its own turf,” Austin said. “But we know that Putin’s malice runs deep. Moscow continues its offensive in the east of Ukraine, especially around Pokrovsk. And Putin is repositioning his troops in Kursk. And the Kremlin continues to bombard Ukraine’s cities and to target Ukraine’s cities and to target Ukraine civilians.”

“That’s an outrage,” he said. “But Ukraine refuses to bend.”

German Defense Minister Boris Pistorius added that he is “a little bit disappointed too” that more air defense systems haven’t yet made their way to Ukraine.

“We agreed in Washington to deliver more Patriot systems, air defense systems of any kind,” he said, “and up until now they haven’t yet arrived in Kyiv.”

On the sidelines of the meeting in Ramstein, Pistorius said Germany will deliver an additional 12 self-propelled howitzers to Ukraine.

CNN’s Rob Picheta, Claudia Otto and Nadine Schmidt contributed reporting