Ukrainian forces have reportedly already started using U.S. artillery to hit targets inside Russia after Washington approved an expanded use of them.

They fired dozens of precision-guided munitions at Russian artillery, troops and a bridge on Sunday, according to the Kyiv Post.

The attack came soon after the Biden administration gave approval for their use.

The weapons used were reportedly M42 missiles fired by the track-mounted M270 rocket launcher and the wheel-mounted HIMARS rocket launcher.

Several missiles may have hit an air defence installatio Belgorod, Russia, the Telegraph reported.

"The president recently directed his team to ensure that Ukraine is able to use U.S. weapons for counterfire purposes in Kharkiv so Ukraine can hit back at Russian forces hitting them or preparing to hit them," a U.S. official told Politico, noting that the administration's stand on allowing long-range strikes inside Russia "has not changed."

Ukrainian officials, including President Volodomyr Zelenskyy, have been clamoring for the United States to allow them to defend Kharkiv, which is 12 miles from the Russian border, from attacks launched inside Russia.

This is a developing story and will be updated.