Police in the German city of Dortmund have arrested a man in connection with an attack on a Bundesliga soccer team's bus that left one player needing surgery.

Police officers patrol outside the stadium before the match between Borussia Dortmund and AS Monaco during the UEFA Champions League Quarter Final First Leg at Signal Iduna Park, Dortmund, Germany April 12, 2017.??[Photo/Agencies]

Police said they found three letters near the stricken bus that indicated the attackers had links to Islamic radicals.

The Borussia Dortmund soccer team had just left a hotel in which it was staying at and was heading for a Champion's League match against AC Monaco when three explosions blew out the bus's rear windows and punctured its back tires.

Club officials said Spanish player Marc Bartra suffered a broken bone in his wrist and had to undergo surgery.

Police said metal shrapnel from the explosive devices was found embedded in headrests on the team bus.

German prosecutors said police had arrested one man with suspected Islamist radical links and were looking for a second.

The match, which was postponed, will be played tonight under close security.

In Berlin a hijacked truck ploughed into a Christmas market on Dec 19 last year, killing 12 and injuring more than 50. Police in Milan shot dead the suspected killer four days later; he was a failed Tunisian asylum seeker who had fled Germany after the attack, which police said was a terrorist incident.