KYIV, Ukraine — Inside a chilly, nondescript warehouse somewhere in Ukraine, young mechanics in hoodies are assembling mortar launchers designed by Ukrainians.

"These are the bigger ones we make, 120 millimeters," says a ginger-haired man named Bohdan, 31, who supervises mortar production for Ukrainian Armor Design and Manufacturing Co., a private arms company. "They look tiny but they can do a lot of damage to the enemy."

Bohdan declined to give his last name for security reasons. NPR also isn't disclosing the location of this factory. Russia often targets military facilities and infrastructure in Ukraine.

He says several hundred of these mortar launchers have been sent to the frontline. But Ukrainian troops need many more.

"Russia has always had more weapons," he says.

As Russia's war on Ukraine enters its third year, Ukrainians are facing a cold reality: Western support for Ukraine is flagging while Russia buys drones from Iran and, according to the U.S., ballistic missiles from North Korea.

Ukrainian Armor and other homegrown arms manufacturers are turning out weapons as fast as they can.

Vladyslav Belbas, the director-general of Ukrainian Armor, says production of mortars and armored vehicles has increased by at least 10 times since Russia's full-scale invasion in February 2022. Its biggest customer is the Ukrainian government, which went from one-off purchases before the war to long-term orders.

"So far we don't have outside investors. The business concept we have at the moment is [to] reinvest our profit in the company, into an extension of production capabilities," says Belbas, during an interview at Ukrainian Armor's headquarters in a Kyiv high-rise.

Arms manufacturers scramble to increase production and develop new weapons

Weapons production in Ukraine began rising in 2014, when Russian military proxies invaded and occupied parts of eastern Ukraine as well as the southern peninsula of Crimea.

Since 2015, Ukrainian Armor has developed and produced two types of armored vehicles. Two years later, it also began manufacturing mortars of all calibers as well as ammunition for those mortars.

"With the full-scale invasion, we had some facilities captured," Belbas says. "So we relocated all of our manufacturing facilities and distributed them in different regions [of Ukraine]."

Ukraine has received advanced weaponry from the U.S. and the European Union such as air defense systems and battle tanks. But Belbas bristles at the perception among some allies that Ukraine has only relied on foreign military aid.

"That is like fully, fully incorrect information," he says.

Ukraine used to have lots of weapons, he says. But after the country gained its independence in 1991 following the collapse of the Soviet Union, its share of the Soviet nuclear arsenal was transferred to Russia, which pledged to respect Ukraine's independence. Ukraine also reduced its anti-tank and anti-infantry weaponry to comply with a Soviet-era treaty governing conventional arms in Europe.

Belbas points out that Russia began increasing its military production, development and investment after Vladimir Putin was elected in 2000. Ukrainian companies did so only after Russia's 2014 takeover of Crimea and parts of eastern Ukraine.

According to the Carnegie Endowment for International Peace, the Russian government plans to increase military and defense spending this year to 6% of its gross domestic product this year. Ukraine's Finance Ministry says Russia's planned defense spending is 2.5 times greater than Ukraine's military budget of $40.7 billion.

Just before and after Russia's full-scale invasion, the U.S. as well as European countries began delivering military equipment to Ukraine.

"That equipment is mainly very old," Belbas says. "It needs to be serviced. It needs to be maintained to be kept operational."

Among Ukraine's locally developed weapons systems is the 2S22 Bohdana, a 155-millimeter NATO-standard self-propelled howitzer mounted on a six-wheel military truck. Its rocket-assisted projectiles can hit targets up to 30 miles away. Ukrainian Armor makes the Bohdana's automotive cabin.

The Ukrainian military used the Bohdana in 2022 to help drive Russian troops off Snake Island, a strategic point in the Black Sea.

Yevhen Hrushovets, a Kyiv lawyer who joined the military, helped coordinate the attack on Snake Island using the Bohdana. At the time, Hrushovets says, the Bohdana had never been used in battle. But when he trained with it, he says he was impressed.

"I saw that it was very powerful, very strong and very reliable," Hrushovets says. "And it was made in Ukraine by Ukrainians."

Ukrainian President Volodymyr Zelenskyy said late last year that Ukraine now makes at least six Bohdanas a month.

Ukrainian arms firms tell NPR that they're designing weapons based on battlefield needs. Serhiy Skoryk, sales director for Kvertus, a company specializing in electronic warfare and reconnaissance systems, says the company's representatives visit the front line every week.

"We are speaking with the heads of electronic warfare in brigades," he says. "And they [tell] us what they want to see, how it will look like, etc., etc."

Skoryk says he learned that drones often stalk soldiers as they evacuate the wounded. So Kvertus is developing items to counter those drones, including special battery-powered backpacks with antennae that can block frequencies used by attack drones.

"You click a button, and it works for at least three hours," he says. The batteries are rechargeable.

"We've made a thousand [backpacks] already," he says. "Our soldiers already use this backpack on the battlefield." The company says it's profitable enough to use its own money for production and research.

Despite its domestic arms production, Ukraine remains dependent on the West

The private arms companies and representatives NPR spoke to harbor no illusions that Ukraine alone is producing enough weapons or ammunition to defend itself from Russia, which has nearly four times the population of Ukraine.

Neither does Ukrainian lawmaker Oleksandra Ustinova, who leads a special parliamentary committee on international support, including military aid.

"For example, we don't have our own gunpowder production, and explosives are dependent on that," she says. "We do have our own production of NATO-standard barrels but not for barrels for widely used howitzers that came from the United States."

Ustinova has spent time in Washington lobbying for military aid to Ukraine but she says Ukraine is also talking to partners about localizing arms production, which is cheaper and faster than waiting for foreign assistance. She also sees a rough road ahead in the U.S. where, she says, Ukraine has become a "hostage of U.S. politics," referring to Congress' failure to approve around $61 billion in military and economic aid for Ukraine.

"We understand that we cannot be guaranteed that there will be more support coming," she says. "We have to be as independent as we can and to have as much production being done in Ukraine as possible."

But that will take time, she says, and Ukraine doesn't have time. Soldiers are rationing ammunition on the battlefield. Air defense also needs ammunition to strike down the missiles and drones Russia shoots at Ukrainian cities nearly every day.

"What we are doing right now is use more drones instead of artillery because we don't have enough [shells]," she says. "We're using these cheap drones...to replace the ammunition at the battlefield. But unfortunately, Russia is bigger and can produce more."

Despite the odds, Ukraine is pushing to keep up. Zelenskyy wants a million drones produced in Ukraine this year. In his New Year's message, he said that Russia "will feel the wrath of domestic production" of arms this year.

Back at Ukrainian Armor's factory, the production of mortars and armored vehicles churns on, stopping only for air-raid sirens signaling another Russian attack.