United Nations High Commissioner for Human Rights noted that nerve agents and radioactive isotopes such as Novichok and Polonium-210 were sophisticated substances that are very hard to get hold of.
The top United Nations human rights official has called on Russia to conduct, or cooperate with, a full independent investigation into Germany's findings that opposition leader Alexey Navalny was poisoned with a Novichok nerve agent, Tuesday.
Navalny has been removed from a medically induced coma and is responding to speech, Berlin's Charite hospital said on Monday.
The hospital has been treating Navalny since he was airlifted to Germany after falling ill on a Russian domestic flight last month.
Moscow says it has seen no evidence he was poisoned.
"It is not good enough to simply deny he was poisoned, and deny the need for a thorough, independent, impartial and transparent investigation into this assassination attempt," Michelle Bachelet, UN High Commissioner for Human Rights, said in a statement.
"It is incumbent on the Russian authorities to fully investigate who was responsible for this crime – a very serious crime that was committed on Russian soil."
Alarm over substance used
German Chancellor Angela Merkel has said her government has concluded that Navalny, 44, was poisoned with Novichok.
According to Britain, Novichok was used against Russian double agent Sergei Skripal and his daughter, both of whom survived, in an attack in England in 2018.
“Navalny was clearly someone who needed state protection ... even if he was a political thorn in the side of the government," Bachelet said.
"The number of cases of poisoning, or other forms of targeted assassination, of current or former Russian citizens, either within Russia itself or on foreign soil, over the past two decades is profoundly disturbing," Bachelet added.
While UN rights office said that they were not in a position to make direct accusations against Moscow in the case, Bachelet noted that nerve agents and radioactive isotopes such as Novichok and Polonium-210 were sophisticated substances that are very hard to get hold of.
"This raises numerous questions," she said. "Why use substances like these? Who is using them? How did they acquire them?"
Bachelet's spokesman, Rupert Colville, cited the Skripal case and the poisoning of Russian defector Alexander Litvinenko, who was killed in London in 2006.
"These are not materials that you can buy in a pharmacy or a farm shop or a hardware store," Colville said of Novichok and Polonium-210, with which Litvinenko was poisoned.
Proper legal processes have not been carried out in previous incidents, resulting in "close to total impunity" in Russia, he said.