US Secretary of State Anthony Blinken has confirmed that President Joe Biden has granted Ukraine permission to use American weapons to strike military targets on the Russian side of the border. He stated this on May 31 during a press conference in Prague, reports UNN with reference to Radio Liberty.
Over the past few weeks, Ukraine has approached us and asked for permission to use the weapons we provide to defend against this aggression, including against Russian troops that concentrate on the Russian side of the border and then attack Ukraine. This is a right for the president, and as you have heard, he has approved the use of our weapons for this purpose
Context
Politico reported on Thursday that the Biden administration secretly allowed Ukraine to use US-provided weapons to strike Russian territory bordering the Kharkiv region in self-defense against enemy attacks.