A German soccer club has apologized to an opposing team's fans after a high-frequency loudspeaker was used to drown out their singing during a league game Saturday.

In a statement on Hoffenheim's website Monday, the Bundesliga club said one employee was responsible for producing the noise, described in his own words as a ''remedy'' to counteract abusive chants by Borussia Dortmund fans directed at the team's main financial backer, Dietmar Hopp.

German daily Bild showed pictures of a speaker placed strategically under the visiting fans' section.

Hoffenheim earlier claimed a fan was responsible, saying in a statement that ''allegations of a deliberate action from the host are unfounded.''

But in a later statement, the club said it was taking ''appropriate legal and disciplinary action against the employee'' and that it was cooperating with the investigation by the Heidelberg police.

''The employee admitted that he was unaware of the consequences of his actions (that were) supposed to have had a rather humorous character,'' the statement said.

''Neither the board of Hoffenheim, nor the president (Peter) Hofmann or Mr. Hopp knew of the existence and use of the device used. All those in charge dissociate themselves from this incident and apologize to all football fans whose experience of the game was affected.''

Hoffenheim said it would ensure such an incident would not be repeated.

Dortmund lost the game 1-0.