Motorists driving out of Leeds have been warned to expect delays this afternoon after traffic was stopped on the M621 motorway.
All lanes were blocked by Highways Agency vehicles while police motorbikes and undercover police response cars made their way to the scene, a few miles southbound of Leeds.
The incident happened at about 1.40pm and traffic began to back up after.
Motorists are advised to be wary of delays for the time being.
West Yorkshire Police has been contacted but it is as yet unclear what the cause of the incident was.
More to follow.