The United States and NATO are shipping weapons into Ukraine at break-neck speed, including highly sensitive items such as shoulder-fired missiles called Man-Portable Air-Defense Systems (MANPADS) that can take down aircraft.
The Western arms deliveries, another one of which is expected to arrive in the coming hours, have been vital to enabling Ukrainians to fight the invading Russian forces far more effectively and fiercely than US intelligence expected.
But moving those amounts of weaponry into the largest conflict in Europe since World War Two carries with it risks that some could fall into the wrong hands -- a possibility the West has considered.
'Risk worth taking'
"Frankly, we believe that risk is worth taking right now because the Ukrainians are fighting so skillfully with the tools at their disposal and they're using them so creatively," a senior US defense official said on Friday when asked about that danger.
Highly portable missiles such as Stinger surface-to-air missiles -- which are a type of MANPAD -- can help win wars, but in the past, they have also been lost, sold, or wound up in the arsenals of extremist groups.
For example, hundreds of Stingers supplied by the United States were seen as key to helping mujahideen rebels drive Soviet forces out of Afghanistan in a conflict that spanned the 1980s and 1990s.
But the United States subsequently spent years trying to recover unused MANPADS from that country and from other conflict zones around the world.
In a Pentagon-financed study in 2019, the RAND Corp. think-tank estimated that upwards of 60 civilian aircraft have been hit by MANPADS since the 1970s, killing more than 1,000 civilians. As of 2019, 57 non-state armed groups were confirmed to possess or suspected to possess MANPADS.
Russia was "far and away the single largest exporter of MANPADS," RAND Corp. said, with more than 10,000 systems sold between 2010 and 2018 to countries including Iraq, Venezuela, Kazakhstan, Qatar, and Libya.
The United States and NATO have not disclosed how many MANPADS have been transferred to Ukraine since the start of the invasion, which is now in its third week.
So far, Russia has not targeted Western weapons convoys headed into Ukraine and the senior US defense official said the United States had not seen any Western-supplied inventory falling into Russian hands.
But that could change.
At a Friday meeting of Russia's Security Council, Defense Minister Sergei Shoigu talked about potential future seizures of Western-made Javelin anti-tank weapons and Stingers. They should be handed to Russian-backed forces in the breakaway Donbass region of eastern Ukraine, he said.
Russian President Vladimir Putin publicly backed the idea.
"As to the delivery of arms, especially Western-made ones which have fallen into the hands of the Russian army - of course I support the possibility of giving these to the military units of the Lugansk and Donetsk people's republics," Putin said.
"Please do this," Putin told Shoigu.
'Special team'
The Pentagon is turning to a special team to respond to increased demand for new weapons sales and requests to transfer existing weapons among US allies as countries including Ukraine scramble to obtain arms following Russia's invasion, three people familiar with the effort said.
The Pentagon's Office of Acquisition and Sustainment, the weapons buyer for the US Department of Defense, has been fielding increased demand from European allies hoping to ship weapons to Ukraine through third-party transfers or to buy arms to bolster their own defenses, the sources said.
The rapid response team was revived in recent days to coordinate and cut through the bureaucracy around sales and transfers while prioritizing requests from allies, the sources said.
The previously unreported effort comes as the Pentagon works to respond to a rapidly changing landscape for arms deals and transfers. The Pentagon made use of the rapid response team during the Trump administration.
"As part of Department of Defense's ongoing supply chain resilience efforts, the Department is evaluating industrial base capacity to produce items critical to our national security and that of our allies and partners. This effort is focused on identifying key supply chain constraints and mitigation actions to improve capacity," a defense official said.
The operation is being run in cooperation with the US Defense Security Cooperation Agency, which oversees weapons sales and transfers to other countries for the Department of Defense.
According to an email seen by Reuters, DSCA recently asked the defense industry for devices that can be used to disable or shoot down drones that were either in stock or could be ready for delivery in 120 days.
"In light of the ongoing crisis in Europe, the USG (US government) continues its efforts to identify effective solutions which would assist Ukraine in the ongoing situation. One of our focus areas is C-sUAS," the message said. Counter small unmanned aerial systems (C-sUAS) technology is used to defeat drones.
Counter-drone devices come in a variety of sizes, prices and formats including the portable radar gun-like Dronekiller made by IXI Electronic Warfare and the Dronebuster from Radio Hill Technologies that can cost in the tens of thousands of dollars each. There are also larger versions of the technology including one that could shield an area the size of a stadium made by SRC Inc. The larger systems can cost in the $3 million to $6 million range, industry executives have said.
The Pentagon has stressed that smaller systems such as Javelin anti-tank systems and Stinger anti-aircraft missiles, which allies are shipping to Ukraine via truck near-daily, are most useful.
"We believe the best way to support Ukrainian defense is by providing them the weapons and the systems they need most to defeat Russian aggression, in particular anti-armor and air defense," Pentagon spokesman John Kirby has said.
In some cases allies are trying to leverage the Ukraine situation to "press for things they wanted even before the conflict," one US official said on condition of anonymity, adding that supply chains are still stressed from the pandemic so there was uncertainty about how this demand could be immediately met.
Countries in Europe - and across the globe - are looking at expanding defense budgets to meet an increasingly uncertain security outlook, with Germany among those promising a sharp increase in spending.