The A14 is closed in both directions at Burton Latimer after a serious crash this evening (Wednesday).
Highways East Midlands said the busy route is shut between Junction 10 at Burton Latimer and Junction 11 at Cranford St John eastbound.
It is closed between Junction 10 and Junction 13 at the A45 roundabout westbound.
Emergency services are at the scene. The severity of injuries and the number of vehicles involved is not yet known.
A police spokesman said: "Due to an ongoing police incident, the A14 between Junctions 10 and 11 will be closed in both directions for the foreseeable future.
"Please avoid the area wherever possible."
A Highways spokesman said: "Please allow extra time for your journey, should you be travelling in the area."