The death toll from explosions at an arms depot in southern Kazakhstan climbed to 13, authorities in the ex-Soviet country said Saturday, adding that three people were still missing.

The blasts occurred at a defence ministry ammunitions depot in the southern Jambyl region, leaving dozens injured and forcing the evacuation of more than 1,000 people from nearby villages.

The Central Asian country's emergencies ministry said Saturday that a 13th body was recovered at the site but had not been identified. 

"The search for three missing (persons) continues," the ministry said in a statement.

President Kassym-Jomart Tokayev announced that Sunday would be a day of national mourning for the military personnel and rescuers who died at the scene of the disaster.

Praising their "heroism," Tokayev wrote on Twitter Saturday that the victims would "always remain in the memory of the people".

on Friday, he acknowledged "systemic problems" with Kazakhstan's ammunitions storage.  

Regular incidents at Kazakhstan's Soviet-era military depots have proven a headache for the government.

Another depot near the southern town of Arys has seen three lethal explosions in the last decade.

The defence ministry said some of the munitions stored at the Soviet-era depot in Jambyl had been transferred from the facility in Arys, where there have been calls to resettle the town's entire population of 45,000.

A video shared online showed a column of smoke billowing from a fire before a powerful explosion sent flames shooting out.

Another showed debris flying through the sky in long arcs as the fire raged. 

The defence ministry said a fire had broken out and "quickly spread to storage facilities where engineering ammunition is stored" causing multiple blasts.