Blasts this week at the Russian-operated Saki military airfield in Ukraine’s occupied Crimea led to the loss of eight Russian combat jets, degrading its navy's Black Sea aviation fleet, Britain said on Friday.

While the damaged jets are only a fraction of the overall aviation fleet, Britain said Black Sea capability would be affected, since Saki is used as a primary operational base.

The base airfield probably remained operational, but its dispersal area had suffered serious damage, Britain's Defense Ministry added in a regular intelligence bulletin on Twitter.

The cause of Tuesday's explosions remains unclear, it added, but the mushroom-shaped columns of smoke seen on witness videos were most likely from up to four areas where ammunition was stored unprotected.

The explosions, which Russia has said killed one and injured five, will prompt its military to revise the threat perception in the region, the ministry added.

Until now, the Ukrainian peninsula, occupied by Russia since 2014, had probably been classified as a safe hinterland.

Satellite pictures released on Thursday showed devastation at the Russian air base hit days earlier in an attack that suggested Kyiv may have obtained new long-range strike capability with potential to change the course of the war.

Russia has denied aircraft were damaged and said explosions seen at the base on Tuesday were accidental.

Ukraine has not publicly claimed responsibility for the attack or said exactly how it was carried out.