In the space of two weeks, Russia’s invasion of Ukraine has set off one of the largest and fastest arms transfers in history.

By road and rail, the Czech Republic sent 10,000 rocket-propelled grenades to Ukraine’s defenders last week alone. In Poland, the provincial airport of Rzeszow located about 60 miles from the Ukrainian border has been so crowded with military cargo jets that on Saturday some flights were briefly diverted until airfield space became available.

On the country’s highways, police vehicles are escorting military transport trucks to the border, with other convoys slipping into Ukraine via snow-covered back roads through the mountains.

The race to deliver arms to Ukraine is emerging as a supply operation with few historical parallels. Western allies, having ruled out putting troops on the ground in Ukraine, have been attempting to equip the country’s thinly spread and outmatched military, some of its soldiers fighting without boots.

With Russian warships holding the Black Sea coast, and Ukraine’s airspace contested, the U.S. is rushing to truck weapons overland before Russia chokes off the roads as well. Pentagon officials said most of what will total $350 million in arms and assistance the Biden administration pledged late last month has been delivered. Congress is considering authorizing billions more. The Defense Department has described its efforts as unprecedented.

Governments once reluctant to transfer arms and antagonize Russia are joining the fray. Sweden, though historically nonaligned, has pledged 5,000 antitank weapons. Berlin—which only three weeks ago was blocking Estonia from transferring German-made howitzers to Ukraine—is now sending more than 2,000 antitank and antiaircraft weapons. Italy, long a passive player in the North Atlantic Treaty Organization, has also promised weapons, and Spain has offered grenade launchers.

The allied effort is buttressed by ordinary citizens in Europe and the U.S., who say they are buying hunting-grade gear online—to circumvent rules against shipping military equipment—and funneling it to friends headed into Ukraine. In Warsaw, a 67-year-old woman is in charge of smuggling night-vision goggles to the country’s defenders. Packed hotels near the Polish-Ukrainian border cater to men asking each other how they can ship body armor to major cities, before Russian troops seize the roads.

Still, Ukrainians say it isn’t enough. In videos posted to social media from his office in Kyiv, with the Ukrainian capital almost encircled by Russian forces, President Volodymyr Zelensky has urged the West to send more weapons and enforce a no-fly zone to stop Russia from carrying out more air attacks on civilians. He pleaded last weekend to members of Congress for combat jets and missiles.

Such appeals are coming not just from the top. Frontline fighters in Ukraine’s Territorial Defense units have used social media to put out a shopping list of their needs, including helmets, binoculars, range finders along with more basic needs such as instant noodles or Q-Tips.

“We need more,” said Andriy Malets, a 53-year-old entrepreneur who signed up to help defend the town of Kryvyi Rih but said he was forced to wait because his local unit has five volunteers for every available gun. Instead, he said, people in Kryvyi Rih now spend their time making Molotov cocktails.