U.S. President Joe Biden has quietly authorized Kyiv to launch U.S.-supplied weapons at military targets inside Russia that are supporting an offensive against the northeastern Ukrainian city of Kharkiv, four U.S. officials said on Thursday.

The decision marks a policy shift by Biden, who had steadfastly refused to allow Ukraine to use American weaponry for strikes inside Russia.

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