A Ukrainian military arms depot located approximately sixty miles from fighting with Russian-backed separatists exploded in dramatic fashion on Thursday, in what is being described by local officials as “an act of sabotage.”

“According to preliminary data … as a result of sabotage, last night at 2.46 AM (0046 GMT), fire and explosions caused the detonation of ammunition at several sites storing rockets and artillery weapons,” Ukraine’s chief military prosecutor Anatoly Matios wrote on Facebook.

The arms depot is located within a military installation in Balakliia, and is used to store thousands of tons of ammunition, equipment, missiles and artillery.  A huge evacuation effort is currently underway, as the series of explosions has already rocked many in the surrounding community.  Concerns about more explosions are mounting, as the depot covers more than a thousand acres of land and houses a reported 138,000 tons of ammunition.  The evacuation zone surrounding the facility has expanded to six miles in every direction in order to reduce the chances of being killed or injured by any subsequent blasts.  Thus far, about 20,000 people have had to flee the area and at least six hundred emergency workers have descended upon the scene of the explosions.

Despite ongoing evacuation efforts, investigators have already begun work on determining the cause of the explosion, with theories that include the possibility of an explosive device being dropped by a drone, according to Ukrainian Defence Minister Stepan Poltorak.  A drone was used in a previous attack on the same location in December of 2015 that was intended to set the depot on fire.  Air space around the facility has been closed in a thirty-one-mile radius.

“A fire broke out,” said Ukraine’s Chief Military Prosecutor Anatoliy Matios. “The fire led to the detonation of munitions.”

Surprisingly, there have been no reports of deaths or injuries tied to the series of explosions.

This latest incident bears a striking resemblance to a similar series of explosions that took place in Svatove, Ukraine in October of 2015.  An ammunition depot exploded, killing two civilians and injuring eight others, and was labeled a terrorist attack by Ukrainian officials.  According to a statement released by the Ukrainian government at the time, the fire that led to the explosions was caused by “the release of a flare that fell onto the territory from outside the base.”

Nearly ten thousand people have died in the conflict between Ukraine and Russian-backed separatists that began with the Russian military annexation of Crimea, Ukraine in 2014.  Fighting between the two groups in the province of Kharkiv and two other eastern regions – Donetsk and Luhansk – has been ongoing ever since, and nations throughout Europe have begun preparing for the possibility that Russia could be planning to retake other swaps of land that once fell under the purview of the Soviet Bloc.