The Soviet government had foreknowledge of the German intentions, provided in part by the British intelligence service, the intelligence transmitted by the Lucy spy ring, and Tunny intercepts. Aware months in advance that the attack would fall on the neck of the Kursk salient, the Soviets built a defence in depth designed to wear down the German armoured spearhead.[25] The Germans delayed the offensive while they tried to build up their forces and waited for new weapons, mainly the new Panther tank but also larger numbers of the Tiger heavy tank.[26][27][28] This gave the Red Army time to construct a series of deep defensive belts.