MOSCOW (AP) — The Kremlin strongly rebuffed Western criticism Thursday and described the thousands of arrests at protests against the jailing of opposition leader Alexei Navalny as a necessary response to the unsanctioned rallies. Many of the people arrested spent long hours on police buses and were held in overcrowded jail cells. Asked about the treatment of detainees, Russian President Vladimir Putin's spokesman said they had to bear responsibility for joining the unauthorized protests. “The situation wasn't provoked by law enforcement. It was provoked by participants in unsanctioned actions,” Putin spokesman Dmitry Peskov said during a call with reporters. Massive protests erupted after Navalny, 44, an anti-corruption campaigner who is Putin’s most determined political foe, was arrested Jan. 17 upon returning from his five-month convalescence in Germany from a nerve agent poisoning, which he has blamed on the Kremlin. Russian authorities deny any involvement and claim they have no proof that he was poisoned despite tests by several European labs.