Tram services have been suspended in Attercliffe after a collision between a new Sheffield tram-train and a lorry
The crash happened on the first day of the new tram-train service.
A spokesperson for Stagecoach Supertram, the operator, said: "We can confirm that a collision took place this afternoon between a lorry and one of our vehicles shortly before 3.20pm on Staniforth Road.
"No-one has been seriously injured however a small number of people were treated at the scene for minor injuries."
They added they are assisting police with their inquiries.
South Yorkshire Police confirmed that road closures are in place, and urged motorists to avoid the area.
A spokesperson said: "At this time no-one is thought to be seriously injured. Please avoid the area and plan alternative routes."
Darren Bailey, a rail enthusiast from Doncaster, says he was on the tram at the time.
He told ITV News: "We'd just left Attercliffe tram stop when I heard this mighty bang.
"People were being thrown all over. I just looked up and saw the side of a lorry."
Mr Bailey added: "It was a bit of a shock to say the least."
Stagecoach Supertram advise passengers to check their Twitter page for travel updates.