A fire broke out at an army camp near Sri Lanka's capital, setting off explosions and killing one soldier before the flames were put out, officials said Monday.

It was not immediately clear what caused the fire Sunday night at the Salawa army camp, about 35 kilometers (22 miles) east of the capital, Colombo. Soldiers managed to douse the flames, but small blasts were still erupting from an ammunition depot but "are not harmful," said military spokesman Brig. Jayanath Jayaweera.

One soldier was killed and another was injured, Jayaweera said.

Thousands of nearby residents who were evacuated from a 5-kilometer (3-mile) radius around the site Sunday night were being allowed to return to their homes Monday morning, except within a kilometer (half a mile) from the camp, which soldiers have yet to declare safe.

Minister of Law and Order Sagala Ratnayake said the fire started at a small arms depot and then spread to other depots where heavy weapons, such as artillery shells, were stored.