Two Royal Mail sites evacuated before a bomb disposal unit carried out a controlled explosion on a suspicious package have reopened.
Avon and Somerset Police said the report of the package came from the Filton depot at 02:17 BST on Friday.
Officers established the package was transported to the Bath delivery office where it was identified.
A controlled explosion was carried out as a precaution, with the contents found to be harmless.
Staff at both sites were evacuated but cordons and diversions have now been lifted.
A Royal Mail spokesperson said: "Earlier today both our Bristol mail centre and Bath delivery office were evacuated following a security incident.
"We are pleased to confirm both sites are now open and fully operational and all our people are safe."
Royal Mail also apologised for any disruption to deliveries.
The closure of the Filton sorting office resulted in delays to train services to Bristol Temple Meads after the road to the rail depot was blocked.
The school bus service for Winterbourne Academy was also disrupted as a result of the Gipsy Patch Lane closure.