 The cost to the Soviet forces had been very high between 1 and 19 April, with over 2,807 tanks lost, including at least 727 at the Seelow Heights.On 20 April, Adolf Hitler's birthday, Soviet artillery of the 79th Rifle Corps of the 1st Belorussian Front first shelled Berlin.Thereafter, Soviet artillery continued the bombardment of Berlin and did not stop until the city surrendered; the weight of explosives delivered by their artillery during the battle was greater than the tonnage dropped by the Western Allied bombers on the city.