 The commanders of two formidable Berlin fortresses agreed to surrender to the Soviets, so sparing both sides the losses involved in further bombardment and assault.The commander of the Zoo flak tower (that had proved impervious to direct hits from 203 mm howitzer shells) was asked to surrender on 30 April; after a long delay a message was sent back to the Soviets on 1 May informing them that the garrison would surrender to the Soviets at midnight that night.The reason for the delay was because the garrison intended to join in the attempt at a breakout.