Police searches are underway at two Royal Mail sorting offices near Bristol and Bath following reports of a “suspicious package”.
Officers descended on the Royal Mail sorting office building in Filton, South Gloucestershire, in the early hours of Friday, 11 September.
It followed reports of a “suspicious package” at the site, which police believe was later transported to the sorting office in Bath.
Staff have been evacuated at both sites and searches are underway, with a bomb disposal squad seen in Bath.
“At 2.17am this morning we were made aware of reports of a suspicious package at the Royal Mail sorting office in Filton,” Avon and Somerset Police tweeted.
“Specialist officers attended and established the package could have been transported to the Bath delivery office.
“Searches are currently being carried out at both locations.
“We don’t believe there to be any risk to the public but ask people avoid the area while the searches take place.”
In a statement, a Royal Mail spokesperson confirmed police were investigating a bomb threat.
“Police are investigating a bomb threat at the Bristol Mail Centre," the spokesperson said.
"This premises is owned by Royal Mail, not Post Office. We do have a nearby depot and staff have been asked by police to evacuate the area along with other local businesses.”
The incident caused significant travel disruption for rail commuters, with services between Temple Meads and Parkway affected.
The 5.46am service from Bristol Temple Meads to London Waterloo - which was due to pass through Bath - was delayed by 30 minutes, while the 6.05am service to Weston-super-Mare departed nine minutes late.
A bulletin on the National Rail website said: "This service has been delayed by police dealing with an incident near the railway."