Complex sentence: In summer 1943 due to unsuccessful military and labour mobilization and spreading armed underground activities of the Soviets, the Germans consolidated the mass repressions in Lithuania, however proclaiming the locals responsible for the acts of sabotage.
Split into simpler sentences: In summer 1943, due to unsuccessful military and labour mobilization and spreading armed underground activities of the Soviets, the Germans consolidated the mass repressions in Lithuania. However, they proclaimed the locals responsible for the acts of sabotage.