German government made an announcement on September 2 that Russian opposition leader Alexei Navalny was poisoned with a Novichok nerve agent, the same type of chemical used in Britain against ex-double agent Sergei Skripal and his daughter Yulia. The discovery raised tensions between Berlin and Moscow.

Tests carried out by the German military experts on Navalny, who is being treated in a Berlin hospital Chairité, have provided “unequivocal evidence of a chemical nerve agent from the Novichok family,” German government spokesman Steffen Seibert said in a statement.

“It is a shocking event that Alexei Navalny has become the victim of an attack with a chemical nerve agent in Russia.

“The government condemns this attack in the strongest terms. The Russian government is urgently requested to provide clarifications over the incident,” he added.

Foreign Minister Heiko Maas said Germany had called in Russia’s ambassador to demand answers on the case.

Navalny, 44, fell ill after boarding a plane in Siberia last month. The pilots took a decision of an urgent landing to deliver him with ambulance to a local hospital in Omsk. Navalny received the first aid at the Omsk hospital near airport, before being flown to Berlin for treatment.

The nerve agent Novichok is a military-grade poison that was developed by the Soviet government towards the end of the Cold War and can be deployed in an ultra-fine powder, liquid or vapour.

The Charite hospital last week reported “some improvement” in Navalny’s condition but he nevertheless remains in a medically induced coma and on a ventilator.

The severity of the poisoning meant that it was too early to determine potential long-term effects, the hospital warned.

Charite doctors said they believed the anti-corruption campaigner was poisoned with a substance that inhibits the cholinesterase enzyme, a feature of nerve agents.

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