Hundreds of people have been forced to leave their homes in Derby after police arrested two men on suspicion of explosives offences.
A major incident has been declared and an evacuation zone has been put in place for around 200 properties.
Officers said they carried out a warrant after “receiving intelligence about materials at an address in Vulcan Street”, leading to the arrest of two Polish men, one in his 40s and one in his 50s. They were still in police custody on Thursday evening.
Derbyshire Constabulary said the investigation was not being treated as terrorism and that there was no wider risk to the community. But they carried out a controlled explosion.
“Residents in the area may have heard a bang in the past hour. This was a controlled explosion, and there is no cause for concern,” said Superintendent Rebecca Webster.
A cordon has been put in place and authorities said homes were evacuated as a safety precaution. Householders living in six streets have been told to prepare to be out of their homes for 24 hours.

A rest centre has been set up at the Salvation Army on Osmaston Road and is being run by Derby City Council. Police have urged residents to prepare to be away from home, including taking medicines or arranging for pets to be moved.
Affected streets include:
- Shaftesbury Crescent – in its entirety
- Vulcan Street – in its entirety
- Reeves Road - in its entirety
- Shaftesbury Crescent – in its entirety
- Harrington Street – from Holcombe Street to Vulcan Street
- Baseball Drive – to Colombo Street
- Cambridge Street - at Reeves Road and Shaftesbury Crescent
Police said they were working closely with Derbyshire Fire and Rescue Service, East Midlands Ambulance Service and the city council.