DORTMUND, Germany — Borussia Dortmund fans protested against their club’s controversial sponsorship deal with a defense manufacturer during the club’s opening Bundesliga match on Saturday.

The second half of Dortmund’s 2-0 win over Eintracht Frankfurt began against a backdrop of banners criticising Dortmund’s three-year sponsorship deal with Düsseldorf-based Rheinmetall, the world’s largest manufacturer of artillery ammunition.

“Not for (swear word) arms industry,” read one sign under a huge banner that simply cursed Rheinmetall with a swear word. “Money first, values ​​second,” read other banners, and another read: “Our values ​​have been run over by a tank.”

“Borussia unites, Rheinmetall kills,” read other banners.

The fans were also noticeably quieter than usual at the start of the second half. They held back their support for several minutes before finally starting again. More than 81,000 fans attended the game in Dortmund’s Westfalenstadion.

Before the game, activists set up a dummy tank in front of the stadium, with one activist wearing a mask with the portrait of Rheinmetall CEO Armin Papperger and holding a red card in his hand.

On Wednesday, the Südtribüne Dortmund fan club signaled the intention of more than 90 fan groups to make their opposition to the deal clear at the start of the second half of Saturday’s game. The club called on fans to bring posters and banners criticizing the deal.

The association also criticised the timing of Dortmund’s announcement of the deal – in May, three days before the team’s defeat to Real Madrid in the Champions League final – saying the news came like a “bombshell”.

Rheinmetall expects record group sales of around 10 billion euros (11.1 billion dollars) this year.

In February, the company announced the construction of a new factory at its existing site in Unterlüß, northern Germany, which will have an annual production capacity of 200,000 artillery shells, 1,900 tons of explosives and possibly rocket engines and warheads.

The company, founded in 1889 as “Rheinische Metallwaaren- und Maschinenfabrik Actiengesellschaft”, was one of the largest armaments companies in Germany during both world wars. During the Second World War, it employed forced laborers.