Russia launches new IRBM at Ukraine, Zelenskyy says Putin is 'terrified'

Russia launched a new intermediate-range ballistic missile on Thursday toward Dnipro in Ukraine, an attack that officials in Kyiv initially said was an intercontinental ballistic missile.

The experimental IRBM was based on a Russian RS-26 Rubezh missile, deputy Pentagon press secretary Sabrina Singh confirmed Thursday during a briefing, without going into any other specific details. She also confirmed that the U.S. was notified "briefly" before the launch.

A U.S. official told ABC News that the United States briefed Ukraine and other close allies and partners in recent days on Russia's possible use of such a weapon in order to help them prepare. According to the official, Russia likely only possesses "a handful" of these experimental missiles.

The launch raises the prospect of nuclear weapons; IRBMs and ICBMs can both be equipped with nuclear warheads. A U.S. official confirmed to ABC News that the ballistic missile Russia fired at Dnipro contained MIRVs, or multiple independently targetable reentry vehicles, meaning it had multiple warheads that hit the target. MIRV technology is used in ICBMs to use multiple nuclear warheads atop the missile so they can strike multiple targets. The missile used Thursday did not carry nuclear warheads.

Ukrainian President Volodymyr Zelenskyy addressed the missile launch Thursday during his evening address, saying a "new ballistic missile was used" and calling it "a clear and severe escalation in the scale and brutality of this war."

Russian President Vladimir Putin, in remarks Thursday following the missile launch, said Russia has the right to use its weapons against the military facilities of countries employing their weapons against Russia.

"We consider ourselves entitled to use our weapons against military objects of those countries that allow to use their own weapons against our objects. In the event of an escalation of aggressive actions, we will respond decisively and in a mirror manner," Putin said.

Putin said Russia used "one of the newest Russian medium-range missile systems" in an attack on Ukraine, adding that it was a "ballistic missile with a non-nuclear hypersonic equipment" and that the "test was successful." 

Russia warned the U.S. 30 minutes before the launch of its new "Oreshnik" missile against targets in Dnipro, Kremlin spokesman Dmitry Peskov told Russian news outlet TASS.

The Kremlin announced earlier this week that Putin had updated the country's nuclear doctrine, a move that lowered the bar for Russia to respond with nuclear weapons. Russian ICBMs are capable of carrying nuclear warheads, although it appeared the missile fired on Thursday was not equipped with one.

Ukraine's military was "95% sure" the strike on Thursday was with an ICBM, a Ukrainian official told ABC News, but added that they were still examining the missile parts on the ground and had not yet reached a final conclusion.

"Today it was a new Russian missile. All the parameters: speed, altitude -- match those of an intercontinental ballistic missile," Zelenskyy initially said in a statement on social media. "All expert evaluations are underway."

The Ukrainian Air Force announced Thursday morning it had tracked the launch of the ICBM, along with six additional missiles, all of which were targeting the Dnipro region. The ICBM appeared to have been launched from the Astrahan region, in Russia's southwest, Ukrainian military officials said.

All of the missiles were launched in about two hours, beginning at about 5 a.m. local time, Ukraine said.

All were targeted at businesses and critical infrastructure, but only the missile that Ukraine identified as an ICBM struck the city, Ukraine said. The six other missiles were shot down. There were no reports of casualties or significant damage, officials said.

U.S. officials said the assessment of the launch, the type of missile and warhead, and the damage in Dnipro was continuing. The distance from what Ukraine said was the launch point to the strike location in Dnipro is about 600 miles, a distance shorter than what an ICBM would be expected to travel.

Two experts told ABC News the projectile, seen in video circulating online, looks likely to be "a ballistic missile with MIRV-ed capabilities."

The missile launch arrives amid concerns that the conflict between Russia and Ukraine could further escalate. This week, Ukraine's military for the first time launched U.S.-made ATACMS missiles toward targets within Russia, days after U.S. President Joe Biden allowed for such use of the long-range weapons.

Putin, in his remarks Thursday, blamed the U.S. for escalating the conflict, saying: "I would like to emphasize once again that it was not Russia, but the United States that destroyed the international security system. And by continuing to fight, cling to their hegemony, they are pushing the whole world into a global conflict."

Kyiv on Tuesday launched six of the ATACMS at targets within Russian territory, according to the Russian Defense Ministry.

Zelenskyy said he would not confirm 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.

Within hours of Russia announcing it had struck down five of the ATACMS on Tuesday, the Kremlin announced that Putin had updated the country's nuclear doctrine.

Following that warning, Ukraine on Wednesday fired long-range British Storm Shadow cruise missiles into Russia for the first time, a Ukrainian military unit involved in the operation told ABC News. At least 10 of those missiles hit an estate in the village of Marino, the unit said.

They were targeting a command post where North Korean army generals and officers were present, the unit said. A U.S. official confirmed to ABC News that a senior North Korean general was wounded in Wednesday's attack by Ukraine in Kursk that used the British Storm Shadow missiles.  The official said the high-ranking general was one of several North Korean casualties in that incident.

More than 10,000 North Korean troops are said to be operating alongside Russian forces in the Kursk region.

Ukraine's 413th Separate Unmanned Systems Battalion, which helped provide fire control for the strikes, told ABC News that there was intelligence showing high-ranking North Koreans were present.

Zelenskyy cast the Russian strike on Thursday as a result of Russia and its leader being "terrified."

"Obviously, Putin is terrified when normal life simply exists next to him. When people simply have dignity. When a country simply wants to be and has the right to be independent," Zelenskyy said. "Putin is doing whatever it takes to prevent his neighbor from breaking free of his grasp."

ABC News' Joe Simonetti, Lauren Minore, Yulia Drozd, Natasha Popova, Tanya Stukalova and Ellie Kaufman contributed to this report.