At least nine people were injured in new explosions on August 9 at a Russian ammunition depot in Siberia where blasts killed one person and injured a dozen more earlier this week.
The local administration in Achinsk district where the depot is located said it had declared a "regional-level emergency" after the new incident.
The Central Military District's press office said "the explosion was caused by a lightning strike."
It said the lightning had hit "an ammunition stack with damaged lightning protection. A shell caught fire and blew up."
The depot's lightning rods were not functioning as a result of damage from the explosions four days ago, the military district said.
The latest reports said nine people had been injured -- including two policemen, a serviceman, and five civilians -- and four required hospitalization.
The Achinsk adminstration said one policeman was in critical condition, and another policeman, a serviceman, and a civilian security guard were in "moderately severe condition."
All, it said, had "cuts, concussions, and craniocerebral injuries," according to Interfax.
Video and still images shared on social media showed first responders and residents with plumes of smoke rising into the sky behind them near Achinsk, in eastern Siberia's Krasnoyarsk region.
Interfax said residents of the village of Kamenka will be evacuated to the nearby community of Malinovka, described as a safe distance away.
The Investigative Committee was investigating possible violations at the same site during the handling of weapons in connection with the previous, August 5 explosions, which prompted a state of emergency in the surrounding region.
There had been plans to shut down the depot, according to a deputy defense minister who visited the region after those blasts.
Reports said the August 5 incident required the evacuation of as many as 16,000 residents who lived within 20 kilometers of the source of the blasts.
Authorities were thought to have put out the resulting fire by the next day, and many locals returned to their homes.
The airspace for 30 kilometers around Achinsk had been closed since the earlier blasts.