Explosions rock German soccer team Borussia Dortmund's bus

NEW YORK (FOX 5 NEWS) - Multiple explosions shattered a window on Borussia Dortmund's team bus in Germany Tuesday evening, sending Spanish defender Marc Bartra to a hospital for surgery on his wrist.

The incident postponed the German team's UEFA Champions League quarterfinal match against Monaco and launched an investigation into the apparent attack.

The devices detonated as the bus left the team hotel. Players crouched and then lay on the floor, bracing for further explosions.

A prosecutor told reporters that a letter claiming responsibility was found near the site of explosions, the AP reported.

"We had to assume, and assumed right from the start, that this was a targeted attack against the team of Borussia Dortmund," Dortmund Police Chief Gregor Lange said.

The team promised additional security for the rescheduled playoff match Wednesday night.

Dortmund tweeted: