Germany's finding that Alexey Navalny was poisoned with nerve agent Novichok shows that only the Russian state could be responsible, the head of the opposition leader's organization said on Wednesday.
"Only the state (FSB, GRU) can use Novichok. This is beyond any reasonable doubt," Ivan Zhdanov, the director of Navalny's Anti-Corruption Foundation, said on Twitter, referring to the FSB internal security and GRU military intelligence services.
Navalny, 44, fell ill after boarding a plane in Siberia last month. He was initially treated in a local hospital before being flown to Berlin for treatment.
His supporters insist he was poisoned and blame President Vladimir Putin's government.
The German government spokesman said Wednesday that tests carried out by the army in consultation with the Charite hospital in Berlin, where Navalny is being treated, had found "unequivocal evidence of a chemical nerve agent from the Novichok family".
The use of a "chemical warfare agent" made it clear the attack was organized by the state, Zhdanov said in separate comments to the Ekho Moskvy radio station.
"And it is responsible for the attempt on the life of a public figure. So naturally we demand the initiation of a criminal case and a normal investigation of all the circumstances of the poisoning."
Russian scientist Leonid Rink, who state media say worked on a government-backed programme to develop Novichok, dismissed the possibility that the substance was used on Navalny.
If it had been used on Navalny, Rink told state news agency RIA Novosti, the opposition leader would be dead, not in a coma.
"He would be taking a long rest in the cemetery, that's all there is to it," Rink said.