The United States has expressed its concern to the Russian government over claims by a Russian opposition activist that he was kidnapped while seeking advice on political asylum in Ukraine and hauled back to Russia, US State Department spokeswoman Victoria Nuland said on Thursday.

Leonid Razvozzhayev, who was wanted in Russia on charges of plotting mass disorder, claims that after consulting with a UN office in Kiev about political asylum last Friday, he was kidnapped off the streets of Kiev by masked men and spirited across the border into Russia in a van.

Russian authorities say Razvozzhayev, who is currently in custody in Moscow, turned himself in and signed a 10-page confession, though the activist says he signed the document after being tortured by his alleged abductors.

“We are quite concerned about allegations that he was forced to confess and that he may have been subjected to torture,” Nuland said during a news briefing.

A spokesman for Russia’s federal Investigative Committee has said Razvozzhayev showed no signs of having suffered from physical or psychological duress, but that it is examining his torture claims.

Russia’s Foreign Ministry on Thursday called the United States’ statements on the case “hypocritical.”

“Not a single American soldier or member of the special forces guilty of the systematic torture of American citizens or foreign citizens in Iraq, Afghanistan, special CIA prisons or Guantanamo Bay has been punished,” the Foreign Ministry said in a statement.