Germany said Monday that two more European laboratories have confirmed its own findings that Russian opposition leader Alexei Navalny was poisoned with a Novichok nerve agent, ramping up the pressure on Moscow to shed light on the case.

Hitting back at doubts raised by Russia about the German investigation, Chancellor Angela Merkel’s spokesman Steffen Seibert said Germany had asked France and Sweden “for an independent review of the German evidence on the basis of new samples from Mr Navalny,” who is receiving treatment in Berlin.