Complex sentence: In April 1940 the Soviet authorities in the annexed territories began to extend their repressive measures towards the general Ukrainian population by arresting and deporting anyone suspected of disloyalty to the Soviet regime.
Split into simpler sentences: In April 1940 the Soviet authorities in the annexed territories began to extend their repressive measures towards the general Ukrainian population. The Soviet authorities began arresting and deporting anyone suspected of disloyalty to the Soviet regime.