The first combat use of Russia’s new IRBM — which Russian President Vladimir Putin called unstoppable — has drawn scrutiny from Western military experts.

Russia’s new ballistic missile flies on a high arc out of Earth’s atmosphere and releases multiple high-speed projectiles, making it challenging but not impossible to intercept

The Pentagon says the Oreshnik is a tweak of Russia’s RS-26 Rubezh missile, an intercontinental ballistic missile (ICBM) that has been tested since 2011.