Russian police officers will be voluntarily checked on lie detectors but the refusal to be tested could spoil their future career in law enforcement, the head of the Russian Interior Ministry's internal affairs division, Lt.-Gen. Yury Draguntsov, said on Monday.

"The polygraph testing is a voluntary thing, and the candidate has the right to refuse, but a refusal can raise questions from the members of the certifying committee and be an indirect reason of the refusal to be hired in the police force," Draguntsov said.

The polygraph testing and the certification of police officers is a part of the ongoing Interior Ministry's police reform that includes changing the name of Russian law enforcers from "militia" to the internationally accepted word "police," and cutting the number of policemen by 20%, while increasing salaries for those who remain.

In an interview with RIA Novosti, Draguntsov also said that every fifth police officer could fail the professional certification since the Interior Ministry's authorities have defamatory information concerning some of them.

"According to preliminary results, at least 15-20 percent of the police heads may fail the certification and be expelled from the police force," Draguntsov said.

He also said that Russian police officers have committed over 50,000 delinquencies in their duties, including 2,000 crimes since the start of the year. Most of the crimes were linked with traffic police officers, migration police as well as investigators and law enforcers keeping public order.

The significant statistics on the police officers' crimes is a result of the Ministry's internal affairs division's work which is aimed at "uncovering latent crimes," Draguntsov told RIA Novosti.