Russia is concerned about future deliveries of Western fighters to Ukraine, so it has accelerated the integration of its A-50 airborne early warning and control and S-400 air defense systems. This is reported by the UK Ministry of Defense in its daily intelligence review of the war in Ukraine. 

Russia has probably begun using the A-50 early warning and air traffic control aircraft for the first time to identify targets over Ukraine for its SA-21 (S-400) long-range air defense missile system, analysts said. This complements the A-50's main task of coordinating fighter aircraft.

Compared to the conventional S-400 ground-based radar, the A-50 can use its radar to detect enemy aircraft at long distances due to its altitude, British analysts emphasized.

Russia may have accelerated the integration of the A-50 and S-400 in part because it is concerned about the prospect of Ukraine deploying Western-supplied combat aircraft.

There is a real possibility that Russia will take a greater risk and deploy the A-50 closer to the front line to effectively use its new role.