The Russian navy has successfully test-fired a prototype hypersonic missile from a nuclear submarine for the first time, the Russian Defense Ministry said earlier this week. 

According to the ministry, the Severodvinsk submarine performed two launches of the Tsirkon (Zircon) hypersonic cruise missile. Tsirkon is a weapon that President Vladimir Putin has boasted as part of a new generation of “invincible” unrivaled arms systems.

“The test-firing of the Zircon missile from a nuclear submarine was deemed successful,” the Russian Defense Ministry said in its statement.

Hypersonic weapons are much more difficult to track or intercept with conventional anti-aircraft weapons.

Russia first test-fired Tsirkon from the water’s surface, and then launched another missile from the Severodvinsk nuclear submarine from a depth of 131 feet. The missile hit a test target in the Barents Sea, the Russian Defense Ministry said.

It also released a grainy video showing the missile lighting up the night sky during the launch. The video was purposely blurred to make a detailed examination by Western intelligence harder.