Complex sentence: On May 13,2013, the news agency Associated Press announced that the Justice Department seized office telephone records for 20 AP reporters for a two-month period in 2012, describing the acts as a "massive and unprecedented intrusion" into news-gathering operations.
Split into simpler sentences: On May 13,2013, the Associated Press announced telephone records for 20 of their reporters during a two-month period in 2012, had been seized by the Justice Department. They described these acts as a "massive and unprecedented intrusion" into news-gathering operations.