NATO's Secretary General Jens Stoltenberg has acknowledged that some allies are sending arms to Ukraine they'd planned to keep for themselves — which he does not think is a problem.

"They have reduced their stocks," he said ahead of a two-day meeting of defense ministers and gathering of the American-led Ukraine Contact Group in Brussels. "But that has been the right thing to do, because it is important for all of us that Ukraine wins the battle."

"If the Russian invasion were to be successful," Stoltenberg warned, "it will make the world more dangerous and it will also make us more vulnerable for further Russian aggression."

But, having reiterated that NATO will be by Ukraine's side "as long as it takes," the secretary general also noted that "The longer this war drags on, the more important it is that we also then are able to replenish these stocks."

Pump it up, Zelenskyy says

Ukrainian President Volodymyr Zelenskyy makes it sound simple for allies to provide his forces with the equipment they need and make up any potential gaps at home.

"Increase the supply of weapons and ammunition to defend against the Russian pressure," he implored European Union leaders gathered last week in Prague. "Increase the manufacture of weapons and ammunition in Europe to be always ready to defend our common space."

These are goals NATO itself has long had for its members. But absent a nearby war, allies have not rushed to streamline weapons procurement and achieve higher interoperability.

Weapons manufacturing is a slow process, and now — as NATO states are having to look deep into their storehouses for items to send Ukraine — governments are also looking for better ways to restock those shelves for themselves.

NATO to allies: 'Dig deeper'

NATO maintains that most allies can do better at meeting the demands of the war in Ukraine without shirking NATO's core missions of deterrence and defense.

"We've invited nations to dig deeper," NATO Assistant Secretary General for Defense Investment Camille Grand told DW in an exclusive interview.

"Ultimately, I do believe that many allies can do somewhere between a little more."

Grand said NATO countries have been improving how they work together to make joint purchases of ammunition and equipment, which provides more security of supply for them and of demand for manufacturers. "The issue here, is how do we take that to a new level?" he explained.

"By having more of those coming up so that allies know they can turn to these mechanisms to get a better price, a faster delivery. But this also benefits industry … to have a very clear demand signal from a group of allies that say, 'Listen, we want to buy X-thousands of artillery rounds, we want to buy X-thousands of anti-tank missiles,' which then enables industry to make the right investment decision."

Estonia is all in

Some allies aren't waiting for new solutions to max out their investments in both Ukraine and NATO. In the Oct 11 update of the Ukraine Support Tracker, maintained by the Kiel Institute for the World Economy, Baltic states and Poland are far out front in terms of contributions as a percentage of their GDP. 

Even more striking, said former Estonian President Toomas Ilves, his country is spending more of its GDP on aid to Ukraine than many NATO allies spend on their own militaries. He told DW Estonia sent its entire collection of Javelin anti-tank missile systems to Ukraine. 

Tallinn has made a clear calculation, Ilves explained. "The idea is that every tank, every T-72 that gets knocked out by an Estonian Javelin in Ukraine is one T-72 we don't have to knock out with our Javelins at home."

Alluding to the allies who keep their purse strings tighter, Ilves said the "Ukrainians are, in a sense, fighting a battle for all of us, and it's a pity there are countries that don't understand this."

Ukraine: Fighting as NATO's 'informal' eastern flank?

Speaking to DW from Kyiv, Ukraine's former foreign minister Pavlo Klimkin agreed that's how the situation is seen in Ukraine, which he calls the "real eastern flank of NATO, although an informal one."

Klimkin calls the supply of weapons a matter of "credibility" for the West, not just with regard to deterring Russia, but also China and any other potential aggressor. He is exasperated that Kyiv's requests for tanks and planes are so "crazy sensitive in the political sense," but he hopes that resistance in Western capitals will be overcome. 

That also goes for moving Ukraine into the category of the "formal" eastern flank of NATO once the war is over, presuming a Ukrainian victory. President Zelensky has requested an accelerated path to NATO for his country.

"It's going to happen," said Klimkin.

Edited by: Ruairi Casey