MOSCOW. Feb 23 (Interfax) - Lev Ponomaryov, one of the veterans of the Russian human rights community, believes a criminal case opened against him and the charges brought are "artificial."

"A criminal case has been opened into libel in relation to Federal Corrections Service Director Yury Kalinin. I have been told to sign a pledge not to leave town," Ponomaryov told Interfax on Saturday.

"I lost a civilian procedure, and a criminal case is being investigated now. I have been questioned as a defendant at the prosecutor's office of Moscow's Central Administrative District. I am convinced that the charges themselves are artificial and have been constructed artificially," Ponomaryov said.

Ponomaryov said the criminal case had been opened after he accused the leadership of the Federal Corrections Service of creating a torture system in Russian penitentiaries.

Russian human rights activists are really worried by the situation in penitentiaries and the observance of human rights in them, he said.

"The penitentiaries have become more closed to human rights activists and civil society. This criminal case should attract society's attention to the horrible conditions in the Russian penitentiary system. I will call witnesses," Ponomaryov said.

Other prominent Russian human rights activists expressed support for Ponomaryov.

"We know that the situation in Russian penitentiaries has deteriorated dramatically," Lyudmila Alexeyeva, the chair of the Moscow Helsinki Group, told Interfax on Saturday.

"The instances of violations of human rights and humiliation have become increasingly more frequent now, and, as a result, revolts and other protests have also become more frequent," Alexeyeva said.

Federal Corrections Service Director Yury Kalinin confirmed to Interfax earlier on Saturday that a criminal case on libel charges had been opened against Ponomaryov.

"Indeed, the Investigative Committee within the Russian prosecution system opened a criminal case under Article 129 of the Russian Criminal Code (libel) against Ponomaryov. An investigator has informed me about this, because the inquiry had been conducted under my request," Kalinin said. He declined from further comment.