Borussia Dortmund chief executive Hans-Joachim Watzke has revealed he considered withdrawing the German club from the Champions League following an attack on their team bus ©Getty Images

Borussia Dortmund chief executive Hans-Joachim Watzke has revealed he considered withdrawing the German club from the Champions League following an attack on their team bus, but opted against it because doing so "would have been a victory for the perpetrators".

Watzke told German magazine Der Spiegel that pulling the team out of the competition was an option after three devices, containing pieces of metal, were detonated near to the bus carrying the Dortmund team to their stadium for the Champions League quarter-final first-leg against AS Monaco on Tuesday (April 11).

The incident, which forced the postponement of the match before it was held at the Signal Iduna Park the following day, left defender Marc Bartra with a fractured wrist.

The 26-year-old Spaniard was today released from hospital after he underwent surgery on the injury suffered during the attack.

It comes as German prosecutors say they are investigating a third claim of responsibility for the explosions, with the Tagesspiegel newspaper reporting they had been sent a letter apparently written by far-right groups in the country.

"We have the letter claiming responsibility," said Frauke Koehler, a spokeswoman for federal prosecutors.

"We are examining it."

Prosecutors had earlier revealed two letters were found at the scene, each claiming responsibility.

Borussia Dortmund players paid tribute to defender Marc Bartra, who was injured during the attack ©Getty Images
Borussia Dortmund players paid tribute to defender Marc Bartra, who was injured during the attack ©Getty Images

One of the letters reportedly referred to the terrorist attack on the Berlin Christmas Market in December and military operations in Syria, although its authenticity has not yet been confirmed.

Lead prosecutor Koehle said authorities had "considerable doubt" over the credibility of another letter, which gave a left-wing extremist motive for the incident.

An "Islamist" suspect was detained earlier this week but has since been cleared of involvement.

Dortmund manager Thomas Tuchel had criticised UEFA for rescheduling the first leg, which the German side lost 3-2, for 24 hours after the incident.

Tuchel claimed European football's governing body made them feel "impotent" and that the club were "completely ignored" in UEFA's decision making process.

The 43-year-old, in charge at the Bundesliga side since 2015, said UEFA's response did not take into account the severity of the attack and was "as if we had beer thrown at our coach".

In response, UEFA insisted the decision was made in "complete agreement with clubs and authorities".

Dortmund won their first Bundesliga match since the attack today as they beat Eintracht Frankfurt 3-1 at the Signal Iduna Park.