The Wall Street Journal reported - quoting US officials - that the United States had secretly modified the advanced Himars missile launchers it supplied to Ukraine, to prevent them from being used to launch long-range missiles at Russian territory.
The newspaper said - in an exclusive report - that US President Joe Biden's administration sees this as a necessary precaution to reduce the risk of a broader war with Moscow.
And the Wall Street Journal highlighted that the United States has supplied Ukrainian forces since last June with about 20 HIMARS missile launchers, and a huge stockpile of satellite-guided missiles with a range of approximately 50 miles.
Those missiles were used to hit Russian ammunition depots, logistical supplies, and command centers of Russian forces on Ukrainian territory.
The newspaper quoted US officials as saying that the Pentagon had made modifications to the HIMARS system, so that it cannot launch long-range missiles, including the tactical missile system that it supplied to Ukraine, which has a range of about 200 miles.
The newspaper's report indicated that the aforementioned secret amendments indicate the extent of the efforts taken by the Biden administration to balance its support for the Ukrainian forces and its keenness to avoid what might lead to an escalation with Moscow.
At the same time, it reflects the fear of US administration officials that Kyiv will not fulfill its promise not to use US arms supplies to strike targets on Russian soil.