COOPER: Tests now indicate an outspoken critic of Russian President Vladimir Putin was poisoned. Alexey Navalny became seriously ill on a flight to Moscow last week, forcing the plan to make an emergency landing. There were disturbing images showing the opposition figure screaming in agony as medics carried him off the aircraft. Navalny was transported to a hospital in Berlin on Saturday. CNN international correspondent, Matthew Chance, is in Moscow.</s>MATTHEW CHANCE, CNN SENIOR INTERNATIONAL CORRESPONDENT: Well, Anderson, German doctors confirming what many already suspected, that Alexey Navalny, an out-spoken Kremlin critic was poisoned. The exact substance has not yet been identified. The clinic in Berlin, where he remains in a coma, says the substance was a type that act on the nervous system. The statement says that Navalny has been treated with a tropine, a medication that's an antidote to some nerve agents and pesticides. The long-term effects of the poisoning, says Navalny's doctors, are still uncertain.
Hospital: Test Results Indicate Russian Opposition Leader Poisoned.