Russia claims it shot down US-made ATACMS missiles and issues nuclear threat

LONDON -- The Russian Defense Ministry said on Tuesday that it defeated a Ukrainian ATACMS attack in the western Bryansk region, shortly before the Kremlin updated its nuclear weapons doctrine to allow for nuclear strikes in response to foreign ballistic missile attacks.

Two U.S. officials also confirmed to ABC News that Ukraine had for the first time fired ATACMS at targets in Russia.

Ukrainian forces fired six "ballistic missiles," the Russian Defense Ministry wrote on its official Telegram page, five of which were downed and the sixth damaged. "According to confirmed data, American-made ATACMS operational-tactical missiles were used," it wrote.

"ATACMS fragments fell on the technical territory of a military facility in the Bryansk region, a fire broke out, it was extinguished," the ministry added.

Bryansk borders Kursk to its west.

A U.S. official provided a differing account of the strike, saying Russia intercepted two of eight total ATACMS missiles launched by Ukraine. The other six were assessed to have hit an ammunition storage site in Karachev, the official said.

The ministry alleged the attack shortly after Kremlin spokesperson Dmitry Peskov told journalists that the changes to Russia's nuclear doctrine -- signed by President Vladimir Putin on Tuesday -- meant "the use of Western non-nuclear rockets by the Armed Forces of Ukraine against Russia can prompt a nuclear response."

One of the U.S. officials said they are not surprised by what they called "irresponsible rhetoric" from the Kremlin, but that the U.S. sees no indications Russia actually plans to use nuclear weapons.

State Department spokesperson Matt Miller told reporters Tuesday he was "unfortunately not surprised" by Russia's decision to alter its nuclear doctrine.

"Since the beginning of its war of aggression against Ukraine, it has sought to coerce and intimidate both Ukraine and other countries around the world through irresponsible nuclear rhetoric and behavior," Miller said. "Despite what Russia says, neither the United States nor NATO pose any threat to Russia."

Miller said the U.S. has "not seen any reason to adjust our own nuclear posture, but we will continue to call on Russia to stop bellicose and irresponsible rhetoric."

Peskov's remarks came after three U.S. officials confirmed to ABC News that President Joe Biden had approved Ukraine's use of the long-range American-made MGM-140 Army Tactical Missile System -- colloquially known as the ATACMS -- to hit targets in Russia's western Kursk region.

Ukrainian President Volodymyr Zelenskyy would not confirm on Tuesday if Ukraine had used ATACMS to conduct a strike on an ammunition depot in the Bryansk region of Russia, but said Ukraine has ATACMS and "will use all of these" against Russia.

"Sorry, no unnecessary details," Zelenskyy said when asked about the possible use of ATACMS against Russia at a press conference in Kyiv on Tuesday.

"Ukraine has long-range capabilities, including domestically produced long-range drones. We now have the extended range 'Neptune,' and not just one. And now we have ATACMS, and we will use all of these," he continued.

Russian Foreign Minister Sergei Lavrov said Tuesday that the reported ATACMS attack is a signal that Western nations "want escalation."

"It is impossible to use these high-tech missiles without the Americans, as Putin has repeatedly said," Lavrov said during a press conference at the G20 summit in Rio de Janeiro.

The extent of U.S. assistance to Ukraine in the battlefield operation of the ATACMS remains unclear. The platform uses an improved inertial guidance system combined with GPS to zero in on designated targets. Kyiv is entirely reliant on the U.S. for replacement missiles.

The Biden administration hasn't publicly confirmed the ATACMS policy change. State Department spokesperson Matthew Miller told journalists at a Monday briefing he would not confirm or deny approval for ATACMS use inside Russia, but said the U.S. response to Russian and North Korean military cooperation in the war "would be firm."

There are now some 10,000 North Korean troops in Russia's Kursk region intended for deployment to the battlefield, U.S. officials have said.

The changes to Russia's nuclear doctrine were unveiled several weeks ago but only signed by Putin on Tuesday, as officials in Moscow expressed anger at the U.S. decision to allow ATACMS use on Russian territory.

The doctrine now says Russia can launch a nuclear attack against a country assisting a non-nuclear country in aggression against Russia that critically threatens the country's state integrity.

Moscow has repeatedly threatened nuclear weapon use against Ukraine and its Western partners throughout its full-scale invasion of the country.

Western leaders including Biden have said that avoiding a direct clash between Russia and NATO is a top priority given the danger of nuclear war.

ABC News' Matt Seyler, Joe Simonetti, Tanya Stukalova, Oleksiy Pshemyskiy and Yulia Drozd?contributed to this report.