Explosives experts have been called to a supermarket after a suspected World War Two bomb was found.
Hertfordshire Police was called to Morrisons in Welwyn Garden City, at 10:57 BST.
Officers were sent to Black Fan Road, along with the fire service and a bomb disposal team, and the area has been cordoned off.
A police spokesperson said: “Road closures are also in place and motorists are advised to avoid the area and seek an alternative route.”
