DORTMUND, Germany -- Borussia Dortmund supporters are planning to start the Bundesliga season with major protests against the club's sponsorship deal with German arms manufacturer Rheinmetall.

"We won't allow ourselves be hitched to your wagon," the supporter association Südtribüne Dortmund said in a statement on behalf of more than 90 Dortmund fan groups on Wednesday.

"We firmly reject the idea that management and its committees at BVB have agreed to use Borussia Dortmund's appeal to improve the public image of an arms company and throw their own values overboard in the process."

Dortmund announced its signing of the three-year sponsorship deal with Düsseldorf-based Rheinmetall on May 29, three days before the team played Real Madrid in the Champions League final.

Rheinmetall is the world's largest maker of artillery ammunition and expects to make record group sales of around 10 billion ($11.1 billion) this year. Trade has been helped by conflicts in Ukraine and elsewhere.

In February, it announced the construction of a new factory at its existing site in Unterluess in northern Germany, with annual production capacity for 200,000 artillery shells, 1,900 tons of explosives and possibly rocket engines and warheads.

Founded in 1889 as "Rheinische Metallwaaren- und Maschinenfabrik Actiengesellschaft," the company was one of Germany's biggest armaments manufacturers during both World Wars. It made use of forced labour during World War II.

News of Rheinmetall's sponsorship with Dortmund came as "a bombshell," according to Südtribüne, which said fan representatives were not consulted at any stage during the negotiations.

"The timing [of the announcement] suggests reactions to this controversial decision were deliberately intended to be overshadowed by reporting on the Champions League final," the group said. "Negative effects on fans were consciously taken into account."

Südtribüne appealed to all Dortmund fans attending Saturday's home match against Eintracht Frankfurt to make their opposition to the deal known.

"Please prepare signs and/or banners with which you can express your criticism at the start of the second half," Südtribüne said.

Organisers of a petition against the deal said they were going to protest outside the stadium with a tank decorated in Dortmund's colours and an activist dressed as Rheinmetall chief executive officer Armin Papperger. They said they will display signs around the stadium and hand out flyers.

Dortmund chairman Hans-Joachim Watzke previously defended the deal.

"When we see every day how freedom must be defended in Europe. We should deal with this new normality," Watzke said.