NATO, THE EU and world leaders have condemned the poisoning of Russian opposition leader Alexei Navalny, after it was revealed he had been poisoned using the Novichok nerve agent.

Those responsible should be brought to justice, European Commission President Ursula von der Leyen said, after Germany said chemical weapons experts had established that Navalny had been poisoned by a Novichok nerve agent.

“I was informed by Chancellor (Angela) Merkel that Russian opposition leader Navalny was attacked with a nerve agent, in his own country,” von der Leyen tweeted.

“This is a despicable and cowardly act – once again. Perpetrators need to be brought to justice,” she added.

The EU’s foreign affairs high representative Josep Borrell said the bloc condemned the poisoning “in the strongest possible terms”.

“The use of chemical weapons under any circumstances is completely unacceptable and a breach of international law,” Borrell said, urging Moscow to investigate the incident “thoroughly and in a transparent manner”.

Alexei Navalny’s case must not go unresolved. Those responsible must be brought to justice.

“I want to condemn in the strongest terms the shocking and irresponsible use of such an agent,” Foreign Minister Jean-Yves Le Drian said in a statement after Germany, where Navalny is being treated after falling ill in Siberia, said he had been poisoned with Novichok.

Navalny, aged 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.

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

It is not the first time Navalny has been physically hurt, nor the first time a critic of the Russian government has been poisoned.

Von der Leyen’s statement added to a growing chorus of western leaders denouncing the attack on Navalny and calling on Russia to account for it.