The poisoning of Alexei Navalny, the Opposition leader in Russia was a “serious breach of international law and requires an international response”, according NATO.
On Friday NATO said that it will not speculate on what action the response would entail but stated that Russia has serious questions to answer.
Russian Kremlin critic Alexei Navalny is currently being treated at Berlin’s Charite hospital.
Navalny, 44, started feeling unwell on a flight returning to Moscow, in August, from the Siberian city of Tomsk, according to his spokeswoman.
After the plane landed in Omsk, Navalny was taken to hospital with suspected poisoning.