Borussia Dortmund bus attack: Police detain 'Islamist' suspect

German police have detained a suspect after three explosions hit Borussia Dortmund's team bus, prosecutors said on Wednesday.

"Two suspects from the Islamist spectrum have become the focus of our investigation. Both of their apartments were searched, and one of the two has been detained," said lead prosecutor Frauke Koehle.

He also confirmed that the investigation was examining a possible "terrorist link".

The blasts damaged the bus as it was travelling through Dortmund to a Champions League match on Tuesday, injuring two people including Dortmund's defender Marc Bartra, who suffered a fractured wrist and glass cuts.

Citing security sources, the Suddeutsche Zeitung newspaper said a letter found near the site referred to the attack on a Berlin Christmas market last year and claimed that German fighter jets were involved in killing Muslims in the the Islamic State's "caliphate".

The statement reportedly starts with a reference to "Allah, the most beneficent, the most merciful" and states that sportsmen and celebrities belonging to "Germany and other crusading nations" were on an IS "kill list".

However, investigators cited by Suddeutsche Zeitung said they were also looking into the possibility that the document was a false trail deliberately laid by another perpetrator.

German press agency dpa said investigators were examining a second letter, posted on an anti-fascism online portal, which said the attack was in retaliation for what it called the club's soft approach toward neo-Nazi and racist fans. The federal public prosecutor said in a statement it had taken over the investigation.

The club posted a message on Tuesday on Twitter that there had been a "bomb explosion".

Windows on the bus were broken in the attack, in which three explosions went off at 7.15pm on Tuesday near the hotel where the team was staying.

Bartra was injured and the Champions League clash with French league leaders AS Monaco was postponed until Wednesday evening.

A message to fans waiting in the Westfallenstadion said: "Dear fans, the team bus had an unfortunate incident on the way from the hotel to the stadium.

"The team bus was heavily damaged and one person injured. He has been transferred to hospital. There is no reason for panic inside the ground. You are safe."

Bartra was operated on for a broken bone in his right wrist and shrapnel in his arm, a team spokesman said.

Borussia Dortmund’s chief executive, Hans-Joachim Watzke, said the coach carrying the players had only just left their hotel and turned on to the road where the explosive devices were hidden behind a hedge. 

Dortmund's goalkeeper, Roman Burki, told the Swiss newspaper Blick: "I was sat in the back row next to Marc Bartra, who was hit by the shards of the burst back window.

'I was sat in the back row next to Marc Bartra, who was hit by the shards of the burst back window'

- Roman Burki, goalkeeper

"After the bang everyone in the bus got their heads down. We didn’t know whether there would be more. The police arrived quickly, sealed everything off. We are all in shock."

Sascha Fligge, Dortmund's spokesman, said on Tuesday night: "I can only say that shortly after leaving the car park there was a detonation… the team heard a loud bang.

"The players had quite different reactions, some threw themselves to the floor, others simply ducked and everyone was totally shocked."