A bomb disposal unit has been called to a police station after a "suspicious device" was found nearby.
Residents were evacuated from their homes and a number of roads were closed after the device was discovered close to Boston Police Station in Lincolnshire.
The Explosive Ordnance Disposal Unit (EOD) was contacted at around 12.15pm.
Shortly before 5pm, Lincolnshire Police said it believed it to be an unexploded device from World War Two, but was awaiting "further assessment" by the EOD.
It said a rest centre had been set up nearby for residents evacuated from their houses.
The force said in a statement: "We are awaiting further assessment of the device from EOD, but we believe it is an unexploded device from World War Two.
"Residents will not be able to return to their homes until it is deemed safe to do so, but a rest centre is available and has been identified as the Municipal Building on West Street.
"If you have been displaced as a result of the incident, please make your way to the rest centre.
LATEST DEVELOPMENTS:
A 100m police cordon was put in place
|GB NEWS/SUPPLIED
"We appreciate your patience while we work to resolve this incident."
A 100m cordon has been put in place at the scene near the police station.
Lincolnshire Police first received a report alerting them to the device shortly after 11.30am.
The force urged residents to avoid the area and warned of several road closures.
The nearby Boston Bus Station was shut as a result of the incident.
Bus operator Brylaine Travel wrote to X: "Boston Bus Station is closed due to an ongoing incident, passengers must wait in the Market Place - NOT at the bus station.
"Thank you for your patience - delays expected."