Highways England has announced that the M1 motorway northbound has been shut from junction 34 and junction 35 near Sheffield.
The agency said that delays are building, but it is not yet clear what the incident is.
The announcement said: "#M1 #Sheffield NB J34 + J35 All traffic is stopped due to a Police incident. Please allow extra journey time, delays building."
UPDATE: The road has reopened, but there are still long delays as of 8.30pm.