Passage: (The ruling PUP reportedly planned a counter-demonstration.) This was a large demonstration outside the National Assembly building in Belmopan which ended in violence.  Protesters threw rocks at the police, who responded with rubber bullets and riot gas. The gunfire and sirens were audible at a distance of at least 1 km.  At least one larger booming sound, significantly louder than gunfire, was heard; the cause of this is unclear.

Question: What was the minimum known distance that the sounds of bullets firing could be heard from?
1 km