Residents have been evacuated following the discovery of an unexploded bomb in Bethnal Green.
The device was discovered by builders in the basement of a building at the junction of Temple Street and Old Bethnal Green Road.
The area has been cordoned off and specialist police officers are attending to deal with the bomb.
Scotland Yard said: "Police were called to the scene an unexploded Second World War device that was discovered by contractors working in Temple Street, Bethnal Green, at around 12.45pm today.
"Road closures are in place and local residents and businesses will be subject to evacuation as a safety precaution. Specialist officers are on scene.
"Motorists are advised to use alternative routes to avoid this area where possible. Significant traffic disruption is expected."
Tower Hamlets Council has put its emergency plan into action including setting up a rest centre for those affected.
A spokesman said: "We have been made aware that an unexploded Second World War bomb has been uncovered at a building site in Bethnal Green.
"The surrounding area is currently cordoned off to pedestrians and traffic.
"We are taking the advice of the Metropolitan Police and London Fire Brigade and will follow the council’s Emergency Planning procedure to ensure residents and visitors to the borough are kept safe.
"Residents and visitors are advised to avoid this area. We have set up a rest centre in a local school with a full Rest Centre Team en route to the school
"Further information will follow in due course."