Sofia  - More explosions rocked an old munitions depot outside Sofia Friday but there was none of the danger of the previous day - while a top army officer resigned over the incident.

Deputy chief of staff Rumen Zokov had borne responsibility for the depot, which on Thursday saw a series of powerful blasts in the eastern suburb of Chelopechene.

Some 20 tons of highly explosive trinitrotoluol (TNT) merely burned without exploding, sparing the Bulgarian capital what could have been a devastating series of explosions.

The defence ministry said infantry and artillery ammunition, bombs, grenades, detonators, explosives and "other pyrotechnical means" had been stored at the depot.

The ordnance was mostly from the Soviet era, brought for de- commissioning to the even older Chelopechene facility, in use since 1918. The blasts were presumed to have been caused by poor storage.

The loudest detonations shattered windows and shook buildings several kilometres around. Despite the force, only two people were injured, reporting lacerations from flying glass shards.

Sofia airport, also east of the city, was closed over much of the day but reopened in the evening, after its runways and area were checked for ordnance possibly strewn by the blast.

Planes arriving from abroad were redirected to Plovdiv, 150 kilometres to the east.

Some 1,700 people living within three kilometres of the depot were evacuated amid concerns that more blasts could damage their homes or infest the area with dangerous unexploded ordnance, but later returned home. (dpa)