ISTANBUL — An explosion at an armament factory in northwest Turkey left at least 12 dead and four injured Tuesday morning.

The blast occurred in the capsule production facility of the factory located in the province of Balikesir, according to the state-run Anadolu Agency.

Balikesir Governor Ismail Ustaoglu said the explosion collapsed the capsule production building and that the surrounding buildings sustained minor damage.

Authorities have opened an investigation.