Bayer Leverkusen "ultra" fan groups have said they will boycott all home games until further notice, with the move coming after a row with the club's hierarchy.
The boycott will begin when the Bundesliga side take on Atletico Madrid in the Champions League on Tuesday.
"We as the group Ultras Leverkusen and all other ultra-orientated groups in the Nordkurve will stop all activities at Bayer Leverkusen home games with immediate effect," a brief statement on the official "ultras" page read.
"This means that, until further notice, we will not attend home games."
The statement did not give any further information, but the group had been involved in a row with the club.
In January, two people were injured when fireworks were thrown from the Leverkusen stands ahead of a defeat to Borussia Monchengladbach.
There were also disagreements between club and fans over banners displayed at the stadium.
But Leverkusen director for fans and social matters Meinolf Sprink told local paper Rheinische Post: "That probably has nothing to do with the boycott."
He added that he believed the ground would be sold out against Atleti and that only some 60 to 70 fans would end up staying away from matches.
"Those fans attending the match will back the team full-scale," he said.