"Bürgermeisters", like the directors of the Berlin utilities, were summoned to appear before Berzarin's staff.As the Soviet armies of the 1st Belorussian Front and the 1st Ukrainian Front converged on the centre of the city there were many accidental 'friendly fire' incidents involving artillery shelling because the spotter planes and the artillery of the different Soviet Fronts were not coordinated and frequently mistook assault groups in other armies as enemy troops.