President Joe Biden secretly allowed Ukraine to use U.S.-made weapons to hit targets inside Russia near the Kharkiv border, U.S. officials said Thursday.

The decision amounts to a policy shift by Biden, who until now steadfastly refused to let Ukraine use American weaponry for strikes inside Russia.

"The President recently directed his team to ensure that Ukraine is able to use U.S.-supplied weapons for counter-fire purposes in the Kharkiv region so Ukraine can hit back against Russian forces that are attacking them or preparing to attack them," said one U.S. official.

The Russian Embassy in Washington and Russia's mission to the United Nations in New York did not immediately respond to a request for comment.

NATO allies have been calling on the U.S. to allow Ukraine to use Western weapons against missile launchers and other military sites inside Russia that are supporting a cross-border offensive that Moscow launched toward Kharkiv this month.

Russian jetfighters flying inside Russia have been backing the drive by launching glide bombs at Kharkiv and Ukrainian defense lines.

Word of Biden's decision broke shortly after the Pentagon said the U.S. policy against the use of U.S. weapons inside Russia had remained unchanged.

"The security assistance that we provide Ukraine is to be used within Ukraine. And we don't encourage attacks, or enable attacks, inside of Russia," said Pentagon spokesperson Sabrina Singh.