Kremlin spokesperson Dmitry Peskov said Tuesday that Russia's new nuclear weapons doctrine means Ukraine's use of Western rockets "can prompt a nuclear response."

Russian President Vladimir Putin has signed a new doctrine lowering the threshold for the use of nuclear weapons should Ukraine use Western-supplied long-range missiles to strike targets inside Russia.

After the U.S. allowed Ukraine to use long-range missiles to hit the Russian mainland, Russia issued a warning message again mentioning its nuclear doctrine

The Kremlin on Monday issued an angry response to a reported U.S. decision to allow Ukraine to use Western-provided missiles to strike deep into Russian territory, accusing Washington of adding “fuel to the fire” in a war Moscow launched almost three years ago.

Kremlin spokesperson Dmitry Peskov said Tuesday that Russia's new nuclear weapons doctrine means Ukraine's use of Western rockets "can prompt a nuclear response."

Ukraine has fired US-made ATACMS missiles into Russia’s Bryansk region, Russia’s Defense Ministry said, in a major escalation on the 1,000th day of war.

Months after sending long-range missiles to Ukraine, the White House has given the green light to use their full force against Russia. This comes after the worst aerial attack against Kyiv in months and questions about how Donald Trump will change the course of the war.

Ukraine suffered what it said was the largest missile and drone attack from Russia since the summer. Chris Livesay has more.