Russia’s Defense Ministry is promising to ramp up missile attacks on the Ukrainian capital in response to Ukraine’s alleged military “diversions on the Russian territory.”

The threat of intensified attacks on Kyiv came  after Russian authorities accused Ukraine of launching airstrikes on residential buildings in a border region of Russia.

Ukrainian officials have not confirmed striking targets in Russia.

However, they claimed their forces struck a key Russian warship with missiles on Thursday. The guided-missile cruiser Moskva, the flagship of Russia’s Black Sea fleet, sank while being towed to port after suffering heavy damage. The circumstances remain in dispute. Moscow acknowledged a fire on board the ship but not any attack.