Complex sentence: In the face of the new German thrust, the Soviets retreated to the Tuutsa River, lost Alakurtti and later withdrew to the Voyta River, where the old 1939 Soviet border fortifications were situated.
Split into simpler sentences: In the face of the new German thrust, the Soviets retreated to the Tuutsa River. They lost lost Alakurtti and later withdrew to the Voyta River, where the old 1939 Soviet border fortifications were situated.