A 'police incident' is disrupting buses in Sheffield city centre, according to travel chiefs.
Stagecoach Yorkshire tweeted at 4.16pm to say: "#SHEFFBUS slight delay to all services in Sheffield centre due to police incident on Commercial Street/High Street area."
A member of the public described seeing a riot van and several police cars in the area.
A small area along Commercial Street, near the Castle Square tram stop, has been sealed off by police.
However, South Yorkshire Police have said they are not aware of any incident in the area at the moment.