Russian military officials said Saturday that they fired a hypersonic missile for the first time in Ukraine to target a weapons storage site in the west of the country.

“The Kinzhal aviation missile system with hypersonic aeroballistic missiles destroyed a large underground warehouse containing missiles and aviation ammunition in the village of Deliatyn in the Ivano-Frankivsk region,” the Russian Defense Ministry said Saturday.

When announcing the development of the Kinzhal hypersonic missile in 2018, Russian President Vladimir Putin described the weapon as “invincible.”

Russia on Saturday also claimed its soldiers have entered the center of the besieged port city of Mariupol in southern Ukraine, which has been shelled for days.

Russian officials say they are “squeezing the encirclement” of the town.

The General Staff of Ukraine’s Armed Forces acknowledged Friday that they have lost access to the Sea of Azov “temporarily” because Russian forces have managed to tighten their grip around Mariupol. Ukrainian officials say Russia has conducted 14 missile strikes and 40 air raids on targets, mainly civilian ones, Ukraine in the past 24 hours.