 On 11 February , the Soviets had about 460 @,@ 000 men , over 3 @,@ 350 artillery pieces , about 3 @,@ 000 tanks and about 1 @,@ 300 aircraft deployed on the Karelian Isthmus . The Red Army was constantly receiving new recruits after the breakthrough . Opposing them the Finns had eight divisions , totalling about 150 @,@ 000 men . One by one , the defenders ' strongholds crumbled under the Soviet attacks and the Finns were forced to retreat . On 15 February , Mannerheim authorised a general retreat of the Second Corps to the Intermediate Line . On the eastern side of the isthmus , the Finns continued to resist Soviet assaults , repelling them in the battle of Taipale . 
