LONDON- Part of Britain's M1 motorway was closed on Tuesday after what police described as a suspicious object was found under a bridge.

The object was discovered at around 0630 GMT and prompted police to close the motorway in both directions between Milton Keynes and Northampton in central England.

"We are urging the public to avoid the M1 as we are currently dealing with a report of a suspicious object," Thames Valley police said in a statement. "The road closures are likely to be in place for some time."

Photographs on social media showed long queues on the motorway, one of Britain's main road arteries between London and the north.

(Reporting by Guy Faulconbridge; editing by Stephen Addison) ((guy.faulconbridge@thomsonreuters.com; +442075424758;))