WATCH: 'Sabotaged' arms depot explodes in massive fireball triggering mass evacuations in Ukraine

Ukrainian authorities suspect “sabotage” triggered a massive explosion at a munitions depot storing missiles that blew out doors and windows in a nearby town.

A huge fireball at the weapons dump caused the evacuation of more than 30,000 people Wednesday from the central Vinnytsia region.

It was the second major incident affecting a large Ukrainian weapons storage site this year.

Police said the flames caused artillery shells at the facility to explode one after the other. Source: AFP

Kiev had blamed a deadly March munitions blast on Moscow and its Russian-backed insurgents fighting Ukrainian forces in the war-wracked east. The Kremlin and its allied militias brushed off the charge as propaganda.

But the ex-Soviet republic's military prosecutor's office said Wednesday it had launched an investigation into possible "sabotage at a military facility".

Initial reports mentioned no fatalities and only two minor injuries from the raging explosions of heavy munitions and air defence missiles at the site.

The Vinnytsia regional administration more than doubled the military's initial estimate of the amount of munitions stored in the depot to 188,000 tonnes after a deeper investigation.

Military general staff spokesman Vladyslav Seleznyov separately told AFP that the arms storage warehouse was "one of the country's largest".

Ukraine's military says the explosion was 'sabotage'. Source: AFP

Explosions at the depot in the town of Kalynivka -- some 175 kilometres southwest of Kiev and about 120 kilometres from the Moldovan border -- could be heard every five to 10 minutes and the streets were all but deserted by its 20,000 inhabitants on Wednesday afternoon.

"People suffered heavy damage," a local resident who gave just the name Antonina told AFP.

"Some homes had their windows and doors completely blown out," she said.

Prime Minsiter Volodymyr Groysman said the explosion was 'no accident'. Source: AFP

President Petro Poroshenko underscored the seriousness of the situation by telling his top military brass and Prime Minister Volodymyr Groysman to report to him directly after visiting the site.

"This is the arsenal of the Ukrainian army, and I think it was no accident that it was destroyed," Groysman said in televised remarks from the scene that hinted strongly at possible Russian or insurgent involvement.

By Wednesday evening the defence ministry said the various shells and missiles had stopped exploding and that the situation at the facility had been brought under control.

But authorities were still putting out forest fires and a demining operation was under way.

Mass evacuation

The Ukrainian army's high command wrote on Facebook that the fire broke out at around 10:00 pm (1900 GMT) Tuesday.

The flames caused artillery shells at the facility to explode one after the other in spectacular but harrowing orange balls of fire that lit up the night sky and shook the ground.

The national police said more than 30,000 people had been evacuated from areas immediately surrounding the storage depot.

"In addition, 180 patients were evacuated from Vinnytsia area hospitals," Ukraine's emergency ministry said.

More than 20,000 people were evacuated from a nearby town. Source: AFP

Officials also shut down surrounding airspace as a precaution to keep exploding missiles from hitting passing commercial jets.

The last major arms warehouse explosion killed one person in the eastern town of Balakliya in March.

Authorities at the time pointed the finger at Moscow and Russian-backed militias fighting Ukrainian troops in a war that broke out in April 2014 and has claimed more than 10,000 lives.

For ten minutes the explosion rocked the area. Source: AFP

Some officials in Kiev then mooted the possibility that the March fire was caused by explosives dropped from a drone.

Both Moscow and the Russian-backed insurgents dismissed the charge outright.

Vinnytsia lies nearly 700 kilometres west of the war zone.

Russia vehemently denies plotting and backing Ukraine's eastern conflict and refers to the fighting as a "civil war" -- a term that particularly irritates Kiev.