The US media outlet CNN has quoted a senior US official as saying the Biden administration lifted a de facto ban on US military contractors deploying to Ukraine early this month.

CNN said on Friday that the decision is aimed at helping Ukraine's military maintain and repair US-provided weapons systems, including F16 fighter jets and Patriot air defense systems that require specific technical expertise.

US-provided military equipment that sustained significant damage in combat used to be transported to NATO countries, including Poland and Romania, for repairs.

By allowing the weapons to undergo maintenance and repair in Ukraine, they will be sent back to the frontlines more quickly.

The Biden administration has strictly limited activities in Ukraine by the US military and contractors since Moscow launched its invasion in order not to provoke Russia.

CNN says, "The shift marks another significant change in the Biden administration's Ukraine policy."