Britain's defense ministry says Russia seems to have suspended operations of its key aircraft fleet after Ukraine announced that it had shot down more than a dozen Russian military planes.

The ministry estimates that Russia has lost two of its nine operable A-50 early warning and control aircraft over the past two months. The A-50s play an important role in operational command.

The ministry said in its intelligence update on Saturday that "Russia has highly likely grounded the fleet from flying" while "internal investigations take place."

The ministry also said, "The loss of this capability providing daily command and control to Russian air operations highly likely significantly degrades the situational awareness provided to air crews."

The ministry added, "It is likely that Russia will have to explore options to bridge this gap, including repurposing aircraft and accepting greater risk to provide the effective air support its ground forces require, but are likely not receiving."

Last month, the Ukrainian military announced that it had shot down 10 Russian Su-34 fighter-bombers, two Su-35 fighter jets and one A-50. The military also said on Friday that it had downed one Su-34 in eastern Ukraine.

Russia's state-run defense company Rostec said late last month that it will resume production of A-50s, indicating that the shoot-downs are dealing a severe blow to the Russian military.