A pair of human rights experts working for the United Nations said they were concerned by Russian prosecution targeting the Anti-Discrimination Center Memorial in St. Petersburg and the Public Verdict Foundation in Moscow.
The non-governmental organizations were charged in April and May respectively for violating a law that requires registration as a "foreign agent" if funding is received from abroad.
U.N. Committee Against Torture Chairman Claudio Grossman and special envoy on reprisals George Tugushi called on Russian Ambassador to the United Nations Alexei Borodavkin to clarify the verdicts.
The envoys said they were seeking assurances the NGOs would not face repercussions "as a result of their legitimate activities, including providing information to the Committee Against Torture."
They said action taken against the two NGOs is "part of a worrying shift" in developments in Russia.
Russian President Vladimir Putin was criticized for backing the NGO legislation last year. He defended the measure as part of a comprehensive transparency initiative.
Putin's critics accuse him of working to silence his opponents. His election to a third non-consecutive term last year was met with widespread protests across Russia.