Russia has been launching heavy 1960s era anti-ship missiles that can cause mass casualties into Ukraine, officials warn

• Russia may be using missiles that cause mass casualties in Ukraine, British officials said.
• Russia is gaining ground in the eastern Donbas region.

Russia has most likely been launching heavy 1960s-era anti-ship missiles into Ukraine, which could cause mass casualties, Ukrainian and British officials have warned.

The UK Defense Ministry said the 5.5 ton Kh-22 missile was designed to destroy aircraft carriers using a nuclear warhead. The agency warned that using the missile in ground attacks "can cause severe collateral damage and casualties," because it's inaccurate. However, the agency did not specify where these missiles are being used.

The ministry added that it thinks Russia is relying on these missiles because it's running short of more precise modern missiles.

The development comes as Russian forces take over more land in the eastern Donbas region. CNN reported that Russia now controls most of Severodonetsk, in the Donbas region. Ukrainian and Russian troops are still engaged in heavy street fighting,

Russia has recently been seeing success in the eastern region of Ukraine. Russian forces invaded Ukraine in February but were met with fierce pushback. The current advancement is a reversal from the start of the war, but experts previously told Insider's Bill Bostock that the success is most likely due to Russia placing a large number of forces in a small area.

The advantage was temporary, experts had said. Since the start of the war, Ukraine has relied on financial support and military supplies from western countries. Officials are now asking foreign leaders for long-range rocket systems to counter Russia's attacks from a distance.