Russia's top investigative agency on Thursday opened a criminal probe against an army soldier accused of sparking a devastating fire at a Russian ammunition depot by dropping a cigarette butt.

The Investigative Committee said the soldier, who voluntarily reported his action, faced charges of breaching fire safety rules. The charge is punishable by up to three years in prison or a fine up to the equivalent of $30,000.

The fire broke out Tuesday at the Donguz depot in the Orenburg region in the southern Ural Mountains. It triggered a series of explosions that destroyed more than 4,000 metric tons of artillery munitions and injured one officer.

Russian military depots see regular fires that rage for days. Experts say they are often rooted in neglect of fire safety rules and poor skills of conscript soldiers.

More than 50 servicemen were killed and over 300 others were injured at fires and other accidents at military ammunition depots in recent years, said Alexander Kanshin, an expert with the Public Chamber, an advisory body for the Kremlin. At a news conference Thursday, he urged the military to stop blowing up old munitions and opt for safer ways of dismantling them.