Ukrainian leaders said "sabotage" was behind massive explosions at an ammunition depot in central Ukraine that prompted the evacuation of more than 30,000 people and the closure of airspace over the region on September 27.
The blasts late on September 26 sparked a massive blaze at the depot near Kalynivka in the Vinnytsya region, some 270 kilometers west of Kyiv, which the country's defense agency said had been brought largely under control late on September 27.
"We have to learn to defend our strategic facilities from sabotage groups," President Petro Poroshenko said during an emergency evening meeting with his top military commanders on the incident. "We will no longer put up with these events."
Ukraine's military prosecutor’s office had said earlier that investigators were treating the explosions and fire as an act of "sabotage," Ukraine’s Security Service (SBU) spokeswoman Olena Hitlyanska said.
Prime Minister Volodymyr Hroysman, who arrived in Vinnytsya hours after the blast, also said "external factors" were behind the incident.
"This is the arsenal of the Ukrainian Army, and I think it was no accident that it was destroyed," he said in televised remarks.
The Vinnytsia regional administration more than doubled the Ukrainian military's initial estimate of the amount of munitions stored in the depot to 188,000 tons.
While Hroysman's remarks suggested he believes the incident was connected with Kyiv's war against Russia-backed separatists, neither he or Poroshenko named specific groups, nations, or individuals they believed to be responsible.
Zoryan Shkiryak, an adviser to the head of the Interior Ministry, said on Facebook that he was "convinced that this is a hostile Russian sabotage" and said it was the seventh fire at military warehouses in Kalynivka.
He said a state commission of inquiry will be set up to investigate the cause of the explosions.
WATCH: Drone video of the explosions provided to RFE/RL's Ukrainian Service
Despite the huge fire and explosions that witnesses said blew out windows and could be heard as far away as Kyiv, no deaths or serious injuries were reported.
The Defense Ministry late on September 27 said in a statement that shells and missiles that had been stored in the depot had stopped exploding and the fire at the depot had been brought largely under control.
Earlier, the chief of Ukraine’s National Police, Vyacheslav Abroskin, said that hundreds of police officers from Vinnytsya, Zhytomyr, Khmelnitskiy, Kyiv, and Chernivtsi regions were providing security and the safe evacuation of people at the site.
Some 600 National Guard troops were deployed to the area to assist with the evacuation of the residents and to ensure the protection of their property from looters, the National Guard said in a statement. Some 1,200 Ukrainian firefighters worked to contain the blaze, Ukrainian news agency UNIAN reported.
After the explosions and fire broke out, local authorities said they shut off electricity and gas supplies and rerouted train and auto traffic around the disaster area.
The airspace within a radius of 50 kilometers from the zone of explosions was closed, Ukrainian Deputy Minister of Infrastructure Yuriy Lavrenyuk said on Facebook.
With reporting by AFP, AP, TASS, and Interfax