"Recent reports by the German doctors claim that @navalny was poisoned. Very unsettling indeed. Thorough investigation is a must. Those responsible must be held to account," the minister tweeted on Monday.
Charite – Universitatsmedizin Berlin, a Berlin hospital Navalny was flown to last Saturday, said in a statement on Monday that tests show he was poisoned. "Clinical findings indicate poisoning with a substance from the group of cholinesterase inhibitors," the hospital said.
Cholinesterase inhibitors block the action of the enzyme cholinesterase, which is responsible for breaking down acetylcholine. This leads to overstimulation of the connection between nerves and muscles.
The Kremlin's critic and anti-corruption activist, Navalny, 44, was flown to the German capital from the Russian city of Omsk where he was treated at a hospital after he fell unconscious during a flight to Moscow. Omsk medics diagnosed a metabolic disease.