Three explosions have hit a bus carrying the Borussia Dortmund football team to their home Champions League quarter-final match against Monaco.
Spain international Marc Bartra was taken to hospital with an injury to his hand, the club said.
The club tweeted (in German) that the other players were safe and there was no danger in or around the stadium.
The first-leg match was postponed and will now be played on Wednesday at 18:45 local time (16:45 GMT).
Pictures from the scene showed the bus’s windows broken and tyres burst in the blasts.
Follow the latest from the Champions League here
Police said that “three explosive charges detonated” at Hoechsten outside the city at about 19:00 local time.
A statement on the North Rhine-Westphalia Dortmund police Twitter site (in German) said that the first indications were that this was an “attack with serious explosives”.
Fans at the 80,000-capacity Signal Iduna Park were told to stay there until it was safe to leave. The stadium has now been evacuated, with police thanking the fans for their co-operation.
Borussia Dortmund said in a statement: “Shortly after the departure of the Borussia Dortmund team bus from the hotel to the stadium there was an incident. The bus has been damaged in two places.”
The Dortmund Twitter page confirmed that Bartra, a 26-year-old defender, was the player hurt, and wished him a speedy recovery.
Spain’s La Marca later said Bartra had been discharged and was back at home.
Dortmund’s CEO Hans-Joachim Watzke said: “There has been an attack with explosives on the team bus.
“The whole team is in a state of shock, you can’t get pictures like that out of your head.”
He added: “I hope the team will be in a position to be able to compete tomorrow on the pitch. In a crisis situation like this, Borussia pulls together.”
One of the Dortmund players, Mathias Ginter, was involved in the Germany-France match that was targeted in the terror attacks in Paris on 13 November, 2015. Another present in Paris, Andre Schurrle, was injured for the Monaco match.
FC Barcelona, Bartra’s former club, tweeted: “All of our support to @MarcBartra, @BVB and their fans.”
Spanish Prime Minister Mariano Rajoy also tweeted his support, wishing Bartra a quick recovery.
Dortmund are currently fourth in the German Bundesliga table.