The US modified HIMARS rocket launchers it sent to Ukraine, according to The Wall Street Journal.
Instead, the launchers work with shorter-range munitions that can strike Russian forces occupying Ukrainian territory, but not reach far into Russia itself.
Since June, the US has supplied Ukraine with at least 20 HIMARS launchers.
Rockets fired from HIMARS have been used to strike Russian ammunition depots, logistics supplies and command centers on Ukrainian territory, according to the Journal.
The Biden administration has so far proved reluctant to provide the weapons, according to an earlier report by The Wall Street Journal, over fears that sensitive technology could end up in the hands of US adversaries.