US President Donald Trump has not seen proof that Kremlin critic and opposition leader Alexei Navalny was poisoned. "I don't know exactly what happened. I think it's tragic, it's terrible, it shouldn't happen," Mr Trump said. "We haven't had any proof yet, but I will take a look at it," he added. Mr Navalny, an anti-corruption campaigner, fell ill on a flight to Moscow, is now in a German hospital after being transferred from a Russian hospital. Nato and Germany say there is "proof beyond doubt" that Navalny was poisoned using Novichok, the same nerve agent that was used in an attack on British spy Sergei Skripal. Mr Trump said he had heard Germany had made a finding that Novichok was used. “So I don’t know exactly what happened. I think it’s sad, it’s tragic. It’s terrible. It shouldn’t happen. We haven’t had any proof yet. But I will take a look. “It is interesting that everybody’s always mentioning Russia, and I don’t mind you mentioning Russia, but I think probably China at this point is a nation that you should be talking about much more so than Russia, because the things that China is doing are far worse,” Mr Trump said. “But you never ask about China, you always asking about Russia. So I would be very angry if that’s the case. And we’ll take a look at the numbers and the documents, because we’re gonna be sent a lot of documents over the next few days,” he added. Mr Navalny fell ill on a flight to Moscow on August 20 and the plane landed in the Siberian city of Omsk, where he was first treated. He has been in an induced coma in a Berlin hospital since being moved to Germany for treatment. German authorities have said that tests showed that he had been poisoned with a chemical nerve agent from the Novichok group.<br/> Britain has previously accused Russia's military intelligence of carrying out the attack on Mr Skripal and his daughter in Salisbury.