A number of La Liga and second division players and club executives have been arrested in Spain as part of an investigation into match-fixing.
Police say 11 people are expected to be arrested in total and at least three matches are being investigated across the country's top three divisions.
A spokesman for La Liga said the police action followed a complaint it had made over a match in May 2018.
"Among those detained are active and retired players," police said.
Presidents and directors of a club have also been arrested the police said.
"The investigation has established that those under investigation came to arrangements with different players to 'fix' at least three games in the first, second and third divisions."
The police said that in the case of one second-division match, more than 14 times the usual amount of money was bet on a game in that league. It did not specify which teams were involved.
Police said bets were made on the outcomes of games as well as other matters including the number of corners awarded.
A lawyer for Huesca, who were relegated from La Liga this season, confirmed that various people at the club had been detained on a warrant issued by a local court.
La Liga side Real Valladolid issued a statement saying the club had "learned of the arrests related to match-fixing" and that they "are the cause of a La Liga complaint".
The statement added: "Real Valladolid rejects any type of conduct or fraudulent behaviour, denouncing corruption among individuals, money laundering, criminal organizations or any type of behaviour that originates or could lead to the distortion and corruption of any sports competition.
"Faced with the arrests made, Real Valladolid maintains, as it has done since the day of its constitution, its commitment and fight against corruption or any type of illicit activity that undermines the integrity of sports competitions."
Valencia also issued a statement saying that reports of "supposed involvement by players and directors of other clubs in illegal gambling and alleged match fixing" are not related to the club, and that "Valencia CF is an entity completely outside of this matter".
A La Liga spokesman said: "We want to thank the police for the extraordinary work done to dismantle what appears to be an organised criminal group dedicated to obtaining economic benefits through the predetermination of football matches.
"During the 2018-19 season La Liga filed eight complaints with the general commissioner of the judicial police for alleged acts related to match-fixing in lower divisions of Spanish football and low-profile friendlies between foreign clubs in Spain.
"We have also sent alerts to the general directorate of gaming on 18 football matches for possible identification and sanction of players from lower divisions who could have bet on their competition.
"La Liga continues to fight to eradicate any scourge against fair play in Spanish football."