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 Russians forces far more effectively and fiercely than U.S. 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.

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 U.S. 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.

reuters.com