Doncaster's St George's Bridge has been closed to motorists in the last few minutes due to a police incident.
The road is closed in both directions with police cars blocking the carriageway near the markets roundabout.
There have been unconfirmed reports that a person has been threatening to jump from the bridge.
Traffic jams are building up around the area and motorists are being advised to find alternative routes.
Bus passengers are also being warned of delays.
More to follow.