Five killed and 300 injured in army base blast

Five people died and 300 were injured when an explosion tore through an ammunition depot at Ecuador's largest military base.

The explosion was caused when a hand grenade detonated accidentally, army spokesman Col Arturo Cadena told reporters.

Communication is cut off with the base in the city of Riobamba, about 100 miles south of Quito.

"You could feel a strong explosion that formed a mushroom cloud like a volcano," Rosendo Coba, a Red Cross volunteer said.

Coba says the blasts caused a fire that spilled out of the military base and engulfed a building.

Col Cadena said earlier that five people - three civilians and two soldiers - were killed.

Health minister Vicente Habze says about 300 people were wounded and relief efforts have been hampered by a power cut in the blast area.

Red Cross spokeswoman Monica Menendez says the explosion occurred at 4pm local time on Wednesday and that army helicopters had been sent to Riobamba to evacuate the seriously wounded.