FRANKFURT, April 11 (Xinhua) -- Three explosions hit the team bus of German soccer team Borussia Dortmund ahead of its first game of UEFA Champions League quarter-final against AS Monaco Tuesday in western German city of Dortmund, injuring one player, local police said.

Photo taken on April 11, 2017 shows the German soccer team Dortmund's bus after explosions in Dormund, Germany. (Xinhua/Ulrich Hufnagel)

A letter claiming responsibility for the incident was found near the site, prosecutor Sandra Luecke told a press conference here, saying however the letter's authenticity wasn't confirmed.

Police said the Dortmund team bus was the intended target of the attack, in which 26-year-old Spain international player Marc Bartra was injured.

Spokesman of the football club Sascha Fligge said Bartra is getting a surgery operation on his wrist and all players of the team were very shocked.

Around 7 p.m. local time, in the Hoechsten district of Dortmund, shortly after the departure of the Borussia Dortmund team bus from the hotel to the stadium Signal Iduna Park for the UEFA Champions League quarter-final against French side AS Monaco, three explosions happened near the bus, damaging the vehicle's windows.

There is so far no indication that the three explosions are a terror attack, reported German Press Agency (DPA), citing local police.

The police said on social media that it was an attack with "serious explosive devices" that could have been placed in a hedge near a car park.

The quarter-final has been postponed until Wednesday and all stadium tours for that day will also be canceled due to further investigation, according to the football club.

Leader of the Social Democratic Party of Germany (SPD) Martin Schulz said on Twitter that he was shocked by the attack.