Widebody; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Inflight Event / Encounter Weather / Turbulence
Flight Crew Took Evasive Action; Flight Crew Returned To Clearance; Flight Crew Diverted
Weather
While flying at FL280 on A596 approaching KM a cell approx 25nm wide crossed the airway.  Tops of cell were well above our altitude.  Asked ATC to deviate around cell to the west. Was denied clearance and told to remain on airway. Asked if we could deviate to the east around the weather. Again denied and told to remain on the airway. Declared Mayday and deviated off the airway 8nm to the west. Was told by ATC we were entering military airspace. My thoughts were; that is not my problem; that is yours. My problem is avoiding going through thunderstorms.
[Report narrative contained no additional information].
Air carrier flight crew approaching ZBAA; the crew reported that they had to use emergency authority in order to deviate around a large thunderstorm.