Complex sentence: The commission estimates that hundreds of thousands of political prisoners have perished in these camps over the past five decades, with atrocities that resemble the horrors of camps that totalitarian States established during the twentieth century.
Split into simpler sentences: The commission estimates that hundreds of thousands of political prisoners have perished in these camps over the past five decades. The Commission's report noted that these atrocities resemble the horrors of camps that totalitarian States established during the twentieth century.