Complex sentence: Mazurov's claim was later verified by Nikolai Ryzhkov, the Chairman of the Council of Ministers under Gorbachev, who claimed that Politburo meetings lasted only for 15 minutes because the people close to Brezhnev had already decided what was to be approved.
Split into simpler sentences: Mazurov's claim was later verified by Nikolai Ryzhkov, the Chairman of the Council of Ministers under Gorbachev. Ryzhkov said that Politburo meetings lasted only 15 minutes because the people close to Brezhnev had already decided what was to be approved.