A court in St. Petersburg sentenced a man to life imprisonment on Thursday for killing and raping four girls between 11 and 20 years of age.

Dmitry Voronenko, 36, a Ukrainian national, raped and strangled his victims, all blondes about 150-cm (5-foot) tall, with their own clothes. He was also charged with the rape of another girl.

"The court ruled that Voronenko deserves capital punishment, which however cannot be applied due to a moratorium," the presiding judge said. "The court therefore believes life imprisonment to be a fair punishment in this case."

The defense had pleaded for leniency, arguing that Voronenko had cooperated willingly with police and had admitted his guilt during questioning.

The judge also took into account that Voronenko had committed the crimes between December 2006 and March 2007, when he was on conditional early release from prison on similar charges. All the murders took place in St. Petersburg.

Voronenko is to be jailed without the possibility of release under amnesty or parole.

An appeal against the verdict can be made to the Supreme Court within 10 days.

Voronenko was arrested late last May as a suspect in the murder of a 12-year-old girl whose body had been found in a St. Petersburg cellar.

Explaining his murders, the killer initially said that as he had no children others should not be able to either. However, in his final statement in court, Voronenko showed repentance. "Punish me, I agree, I am guilty," he said, according to parents of one of his victims.

Psychiatrists had earlier found Voronenko sane and fit to stand trial.

Earlier reports said the parents of the murdered girls planned to seek the lifting of Russia's moratorium on the death sentence.