A massive explosion at a naval base on Cyprus Monday killed 12 people, wounded 62 others, and knocked out power to half the Mediterranean island.

The commander of the Cypriot navy, Andreas Ioannides, was among those killed.

Cypriot President Dimitris Christofias has declared three days of official mourning, with the nation's flags to be flown at half staff. He sent his condolences to the families of the victims, calling it a black day for Cyprus.

Authorities say a brush fire near the Evangelos Florakis Naval Base in southern Cyprus set off stored gunpowder. Containers of gunpowder were seized in January 2009 from an Iranian ship headed to Syria. Officials have ruled out sabotage.

A government spokesman says officials met last week to discuss how the gunpowder could be stored more safely.

Cypriot Defense Minister Costas Papacostas and National Guard Chief Petros Tsalikides resigned after Monday's blast.