BRUSSELS When the Soviet Union collapsed, European nations grabbed the peace dividend, drastically shrinking their defence budgets, their armies and their arsenals.

With the rise of Al-Qaeda nearly a decade later, terrorism became the target, requiring different military investments and lighter, more expeditionary forces. Even Natos long engagement in Afghanistan bore little resemblance to a land war in Europe, heavy on artillery and tanks, that nearly all defence ministries thought would never recur.

But it has.

In Ukraine, the kind of European war thought inconceivable is chewing up the modest stockpiles of artillery, ammunition and air defences of what some in Nato call Europes bonsai armies, after the tiny Japanese trees. Even the mighty United States has only limited stocks of the weapons the Ukrainians want and need, and Washington is unwilling to divert key weapons from delicate regions like Taiwan and Korea, where China and North Korea are constantly testing the limits.

Now, nine months into the war, the Wests fundamental unpreparedness has set off a mad scramble to supply Ukraine with what it needs while also replenishing Nato stockpiles. As both sides burn through weaponry and ammunition at a pace not seen since World War II, the competition to keep arsenals flush has become a critical front that could prove decisive to Ukraines effort.

The amount of artillery being used is staggering, Nato officials say. In Afghanistan, Nato forces might have fired even 300 artillery rounds a day and had no real worries about air defence. But Ukraine can fire thousands of rounds daily and remains desperate for air defence against Russian missiles and Iranian-made drones.

A day in Ukraine is a month or more in Afghanistan, said Ms Camille Grand, a defence expert at the European Council on Foreign Relations, who until recently was Natos assistant secretary-general for defence investment.

In the summer in the Donbas region, the Ukrainians were firing 6,000 to 7,000 artillery rounds each day, a senior Nato official said. The Russians were firing 40,000 to 50,000 rounds per day.

By comparison, the United States produces only 15,000 rounds each month.

So the West is scrambling to find increasingly scarce Soviet-era equipment and ammunition that Ukraine can use now, including S-300 air defence missiles, T-72 tanks and especially Soviet-calibre artillery shells.

The West is also trying to come up with alternative systems, even if they are older, to substitute for shrinking stocks of expensive air-defence missiles and anti-tank Javelins. It is sending strong signals to Western defence industries that longer-term contracts are in the offing and that more shifts of workers should be employed and older factory lines should be refurbished. It is trying to purchase ammunition from countries such as South Korea to backfill stocks being sent to Ukraine.

There are even discussions about Nato investing in old factories in the Czech Republic, Slovakia and Bulgaria to restart the manufacturing of Soviet-calibre 152 mm and 122 mm shells for Ukraines still largely Soviet-era artillery armoury.

But the obstacles are as myriad as the solutions being pursued.

Nato countries often with great fanfare have provided Ukraine some advanced Western artillery, which uses Nato-standard 155mm shells. But Nato systems are rarely certified to use rounds produced by other Nato countries, which often make the shells differently. That is a way for arms manufacturers to ensure that they can sell ammunition for their guns, the way printer manufacturers make their money on ink cartridges.

And then there is the problem of legal export controls, which govern whether guns and ammunition sold to one country can be sent to another one at war. This is the reason the Swiss, claiming neutrality, refused Germany permission to export to Ukraine needed anti-aircraft ammunition made by Switzerland and sold to Germany. Italy has a similar restriction on arms exports.

One Nato official described the mixed bag of systems that Ukraine must now cope with as Natos petting zoo, given the prevalence of animal names for weapons like the Gepard (German for cheetah) and the surface-to-air missile system called the Crotale (French for rattlesnake). So re-supply is difficult, as is maintenance. A Ukrainian soldier holds a Next Generation Light Anti-tank Weapon that was used to destroy a Russian armoured personal carrier in Irpin, north of Kyiv, on March 12. PHOTO: AFP The Russians, too, are having resupply problems of their own. They are now using fewer artillery rounds, but they have a lot of them, even if some are old and less reliable. Facing a similar scramble, Moscow is also trying to ramp up military production and is reportedly seeking to buy missiles from North Korea and more cheap drones from Iran.

Given the Russian annexation of Crimea in 2014 and the war in the Donbas region, Natos new military spending goals 2 per cent of gross domestic product by 2024, with 20 per cent of that on equipment instead of salaries and pensions seem modest. But even those were largely ignored by key member countries.

In February, when the war in Ukraine began, stockpiles for many nations were only about half of what they were supposed to be, the Nato official said, and there had been little progress in creating weapons that could be used interchangeably by Nato countries.

Even within the European Union, only 18 per cent of defence expenditures by nations are cooperative.

For Nato countries that have given large amounts of weapons to Ukraine, especially front-line states like Poland and the Baltics, the burden of replacing them has proved heavy.

The French, for instance, have provided some advanced weapons and created a 200 million (S$286 million) fund for Ukraine to buy arms made in France. But France has already given at least 18 modern Caesar howitzers to Ukraine about 20 per cent of all of its existing artillery and is reluctant to provide more.

The European Union has approved 3.1 billion to repay member states for what they provide to Ukraine, but that fund, the European Peace Facility, is nearly 90 per cent depleted.

In total, Nato countries have so far provided some US$40 billion (S$55 billion) in weaponry to Ukraine, roughly the size of Frances annual defence budget.

Smaller countries have exhausted their potential, another Nato official said, with 20 of its 30 members pretty tapped out. But the remaining 10 can still provide more, he suggested, especially larger allies. That would include France, Germany, Italy and the Netherlands.

Natos secretary-general, Jens Stoltenberg, has advised the alliance including, pointedly, Germany that Nato guidelines requiring members to keep stockpiles should not be a pretext to limit arms exports to Ukraine. But it is also true that Germany and France, like the United States, want to calibrate the weapons Ukraine gets, to prevent escalation and direct attacks on Russia. More On This Topic Nato chief says decision on supplying Patriot missiles to Ukraine lies with Germany EU urges cooperation as members refill military stocks amid arms supplies to Kyiv The Ukrainians want at least four systems that the West has not provided and is unlikely to: long-range surface-to-surface missiles known as ATACMS that could hit Russia and Crimea; Western fighter jets; Western tanks; and a lot more advanced air defence, said Mr Mark F. Cancian, a former White House weapons strategist who is now a senior adviser at Washingtons Centre for Strategic and International Studies.

The ATACMS, with a range of ome 190km, will not be given for fear they could hit Russia; the tanks and fighter jets are just too complicated, requiring a year or more to train in how to use and maintain. As for air defence, Mr Cancian said, Nato and the United States deactivated most of their short-range air defence after the Cold War, and there is little to go around. Producing more can take up to two years.

Maintenance is key, but there are clever answers for relatively simpler equipment, like the M-777 howitzer given to Ukraine. With the right parts, a Ukrainian engineer can link up to a US artillery officer in Fort Sill, Oklahoma, and get talked through maintenance over Zoom.

Washington is also looking at older, cheaper alternatives like giving Ukraine anti-tank TOW missiles, which are in plentiful supply, instead of Javelins, and Hawk surface-to-air missiles instead of newer versions. But officials are increasingly pushing Ukraine to be more efficient and not, for example, fire a missile that costs US$150,000 at a drone that costs US$20,000.

Already, some weapons are running low.

As of September, the U.S. military had a limited number of 155 mm artillery rounds in its stockpiles, and limited numbers of guided rockets, rocket launchers, howitzers, Javelins and Stingers, according to an analysis by Mr Cancian.

The shortage in 155mm artillery shells is probably the big one that has the planners most concerned, he said.

If you want to increase production capability of 155 shells, he said, its going to be probably four to five years before you start seeing them come out the other end. NYTIMES More On This Topic Ukraine receives first delivery of NASAMS air defence systems US pushes allies to assemble patchwork air defences for Ukraine