Underage killers committed up to 37 murders in the Khabarovsk Territory in Russia's Far East last year, the head of the local police unit charged with youth affairs said Thursday.

"Seventy-eight percent of the children who have committed especially serious offenses come from families we might call well-off," Dimitri Savin told a press conference.

He cited the example of four adults killed in the village of Chegdomin by drunken teenagers to whom the victims had refused to give money for more alcohol.

Another case involved the murder of a 16-year-old girl, killed by two of her friends out of jealousy and thrown into a tar pit, he said.

Savin said that girls have been responsible for committing many more crimes in recent years. He said that in 2006, of 3,000 offenses committed by teenagers 351 were carried out by girls.