Three explosions went off next to Borussia Dortmund's team bus on Tuesday night, leaving one player injured and causing the club's Champions League quarter-final first leg against Monaco to be postponed.
According to local police, the blasts were specifically aimed at the bus and a letter claiming responsibility for the attack was recovered from the scene. Investigators are examining the letter's authenticity.
The incident occurred as the team left their hotel in the suburb of Dortmund-Höchsten shortly after 7.00pm local time. Marc Barta, the Dortmund defender, broke a bone in his right wrist in the incident and underwent surgery in hospital.
Tuesday's match was subsequently put back until 5.45pm BST on Wednesday, with the decision to postpone made 15 minutes prior to the game's scheduled kick off at Signal Iduna Park, Dortmund's home ground.
Supporters were kept inside the stadium until police established that they would be safe to leave. The Monaco fans chanted Dortmund songs in a show of solidarity, while Dortmund encouraged residents of the city to house travelling Monaco supporters who still wish to attend Wednesday's rescheduled fixture.
Polizei Nordrhein-Westfalen Dortmund, the local police force, praised fans for the way they dealt with developments, tweeting: “High praise to all stadium visitors! Without problems almost all left the stadium and are on the way home!”
Hans-Joachim Watzke, Dortmund's CEO, revealed that the club's players were in shock following the attack, writing in a statement on Facebook: “There has been an attack with explosives on the team bus. Three explosive devices were placed and triggered on the edge of the road.
“The whole team is in a state of shock, you can't get pictures like that out of your head. 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,” he added.
A statement by local police released shortly after news broke of the incident read: “In the run-up to the Champions League match of the BVB against the AS Monaco, there was an explosion near the BVB team team bus shortly after 7pm.”
“The event location is Wittbräuckerstraße / Schirrmannweg in Dortmund-Höchsten. According to current knowledge the disks of the bus (whole or partial) were broken and one person was injured.
“It is not yet possible to say exactly what the explosion was or exactly where something exploded.”
A subsequent statement revealed more details about the incident, with police saying the attack used “serious” explosives which “may have been hidden in a hedge near a parking lot.”