MOSCOW, November 3 (RIA Novosti) - Russian President Dmitry Medvedev signed on Tuesday a law on harsher punishments for top criminal bosses.

The new law concerns those criminals known in Russia as 'thieves-in-law' - or gang leaders at the top of the criminal hierarchy.

"Punishments for the involvement in criminal groups have been raised to the maximum," Medvedev said at a meeting with Alexander Bastrykin, the head of Russia's Investigative Committee.

The Russian leader also said that people who "occupy high-up positions in the criminal hierarchy" will face "15-20 years in jail, or life imprisonment."

"We are also talking about people who do not attempt to conceal their identification with the criminal world. In its very essence, membership of such a criminal group constitutes a criminal act and this is enough to bring these people to penal responsibility."

"I would like this law to be applied effectively by all investigative authorities. We need to learn to use it properly," Medvedev added.

One of the most famous of Russia's thieves in law - Vyacheslav Ivankov, also known as Yaponchik - died last month of wounds sustained in July when he was shot by a sniper after leaving a Moscow cafe.