- Ukraine fired US-made ATACMS missiles at Russia, the Kremlin said.
- It's the first time Ukraine has used the weapons against Russia.
- One caused a fire at a military facility in Russia's Bryansk region.
Ukraine fired US-supplied ATACMS long-range missiles into Russia for the first time, marking a significant escalation in the war.
It comes after President Joe Biden this week authorized the use of the powerful missiles by Ukraine in a major change in US policy.
Five Army Tactical Missile Systems, or ATACMS, were shot down and one caused a fire at a military facility in Russia's Bryansk region, the Kremlin said.
There were no injuries or substantial damage, the Russian Ministry of Defense added.
Ukrainian media also reported the strike, with a defense source telling RBC-Ukraine that ATACMS had been used in a successful attack on a military facility in Bryansk.
Military experts previously told Business Insider that the ATACMS restrictions were slowing Ukraine's progress by making it harder to target the source of Russian attacks.
Earlier on Tuesday, President Vladimir Putin approved an update to Russia's nuclear doctrine, widening the scenarios in which it would consider a strike.
The move seemed a direct response to US approval for Ukraine to use US-made long-range missiles to attack Russia.
Russia has long warned Western powers against Ukraine using the weapons in attacks on its territory, and the Russian Foreign Ministry on Monday said any such strikes would result in a "an appropriate and tangible" response.
Ukraine has used ATACMS, that have a range of around 190 miles, as well as French and UK-made Storm Shadow missiles in strikes deep in occupied east Ukraine and Crimea, but not until today on Russia itself.
Biden had reportedly been concerned that lifting the restrictions on using long-range weapons in attacks on Russian territory could escalate the conflict.
His decision comes only months before President-elect Donald Trump takes office. Trump may decide to reverse the order.
In recent weeks, Russia has escalated its attacks on Ukrainian infrastructure and cities and has massed a force of 10,000 troops, including North Koreans, to drive Ukrainian forces out of the territory they occupy in Kursk, Russia.
Jon Finer, the US deputy national security advisor, said Monday that the US had made it "clear to the Russians that we would respond" to recent escalations, citing the involvement of North Korea.