THE secretary-general of Nato has condemned the “appalling assassination attempt” on Russian opposition politician Alexei Navalny and called on Moscow to answer questions.

Navalny, a Kremlin critic and corruption investigator, fell ill on a flight to Moscow and has been in an induced coma in a Berlin hospital since he was flown to Germany for treatment more than a week ago.

German authorities have said tests showed that he had been poisoned with a chemical nerve agent from the Novichok group.

Jens Stoltenberg, who chaired a meeting of Nato ambassadors, said: “There is proof beyond doubt that Navalny was poisoned using a military-grade nerve agent from the Novichok group.

“The use of such a weapon is horrific.

“Any use of chemical weapons shows a total disrespect for human lives and is an unacceptable breach of international norms and rules. Nato allies agree that Russia now has serious questions it must answer.”