This is stated in the film Arming Ukraine on the American TV channel CBS News. It was announced by the pro-Kremlin media, and in Ukraine, it was published by the website "Strana". The film says that the US loses control over military weapons after crossing the border, that only 30-40% of supplies from the West reach the front, and the rest goes to the "black market". That is why a system of weapons supervision should be created.