Police are investigating reports of an explosion in Romford, northeast London.
The incident is not currently being treated as terror-related.
People have been urged to avoid the area around Farnham Road.
Havering police officers tweeted: “Officers along with other emergency services are currently on scene in Farnham Road #HaroldHill, following reports of an explosion.
“Cause not known but not currently being treated as terror-related. We await updates re any injuries. Pedestrians & motorists advised to avoid the area.”