Dortmund bus (INSERT) Bartra who was injured in the blast

German investigators are looking into the possibility that explosions targeting a bus carrying players of soccer club Borussia Dortmund may have been carried out by Islamists militants, the Sueddeutsche Zeitung newspaper reported on Wednesday.

It said a letter left near the scene of the attack on Tuesday claimed it was in retaliation for German military reconnaissance missions against Islamic State in Syria.

The newspaper also said that the letter may be a deliberate attempt by the perpetrators to mislead investigators.

The Federal Public Prosecutor said in a statement it had taken over the investigation and would hold a news conference soon. (Reuters/NAN)