MEXICO CITY -- Legendary Mexican football player Rafael Marquez has categorically denied any connection to a drug trafficking organization after being sanctioned by the U.S. Treasury Department on Wednesday.

Marquez, 38, and a well-known band leader are among 22 people sanctioned by the U.S. Treasury as a result of a multiyear investigation of the drug trafficking organization allegedly headed by Raul Flores Hernandez, the department said in a statement.

It will also sanction 43 entities in Mexico, including a football team and casino.

It is the single largest such designation of a drug trafficking organization ever by its Office of Foreign Assets Control, the statement said.

Marquez, 38, is a former defender for Barcelona, Monaco and the New York Red Bulls who currently plays for the Mexican football club Atlas in Guadalajara and was a long-serving captain of the Mexican national team. He did not practice with Atlas on Wednesday.

Speaking at a news conference later Wednesday evening, Marquez said: "Today several news outlets reported that I am part of an investigation conducted by the U.S. Treasury Department for alleged ties to criminal organization. I categorically deny any type of relation with this organization and with what has been stated in several news reports.

"I understand the legal situation that I find myself in, and I will immediately work on clearing up the facts alongside my team of attorneys.

"I reiterate that I have never participated in any of these organizations that have been mentioned in these reports, and want to reiterate my duty to assist the various authorities and corresponding governments in a punctual manner and maintain the media informed.

"I also want to ask for respect for my family and towards my situation, because it is not a normal situation -- it is a difficult situation, and I ask for as much respect as possible.

"I also thank those who have sent me messages of support; I know that many people are with me and I will not disappoint them.

"Just as I have approached my professional career, today is my most difficult challenge. I will try to clear this up when I can and be the Rafa Marquez everyone knows."

Flores Hernandez allegedly operated independently in the northern city of Guadalajara but maintained alliances with the Sinaloa and Jalisco New Generation cartels. According to federal court records, Flores Hernandez was arrested July 20 and extradition is pending.

The Mexican Attorney General's Office also seized related assets on Wednesday, including the Grand Casino near Guadalajara, according to the U.S. statement.

OFAC Kingpin action targets 22 Mexican Nationals & 43 entities-the largest Kingpin designation against a Mexican drug network pic.twitter.com/RaGfecYahf — Treasury Department (@USTreasury) August 9, 2017

Mexican prosecutors said they were working closely with U.S. authorities on the investigation and added that Marquez came voluntarily to the Attorney General's Office to provide a statement.

Mike Vigil, former chief of international operations for the U.S. Drug Enforcement Administration and author of the book "Deal," said the 64-year-old Flores Hernandez has been in the business since the 1980s.

"He is extraordinarily crafty in the way he strategizes and the way that he navigates between cartels," Vigil said.

But, the former agent added, Flores Hernandez has remained a mid-level drug trafficker, never forming what one would call a cartel, and of late had aligned himself with Nemesio Oseguera of the Jalisco New Generation Cartel.

Vigil said Flores Hernandez had a real talent for laundering drug proceeds by setting up front companies. He said it would be difficult to imagine that Marquez didn't know who he was dealing with because Flores Hernandez has been around for so long.

"Raul Flores Hernandez has operated for decades because of his longstanding relationships with other drug cartels and his use of financial front persons to mask his investments of illegal drug proceeds," John E. Smith, director of the Office of Foreign Assets Control, said in the statement.

Federal drug trafficking indictments against Flores Hernandez were returned in March in Washington and the southern district of California.

The U.S. government referred to Marquez and 34-year-old "norteno" singer Julio Cesar Alvarez, better known as Julion Alvarez, as people with longstanding relationships with Flores Hernandez who "have acted as front persons for him and his [drug trafficking organization] and held assets on their behalf."

Alvarez has been nominated for Latin Grammys and has won Billboard awards. His latest album, "Not a Devil, nor a Saint," released in May, was his fifth No. 1 on the Billboard list of regional Mexican music.

Alvarez's manager did not immediately respond to an email request for comment. A spokesman for Universal Music, the parent company of Alvarez's record label Fonovisa, declined to comment.

But Alvarez posted a video to his Facebook page saying "absolutely nothing is going on."

Alvarez called Marquez a friend and sent him a hug: "Everything they are saying there can be cleared up."

President Enrique Pena Nieto's office confirmed Wednesday that a photo of the president and Alvarez had been removed from Pena Nieto's Instagram account. The office declined further comment.

The U.S. statement did not say that Marquez or Alvarez face charges in the United States.

Marquez is famed as a tenacious defender whose crunching tackles have sometimes seen him sent off in high-profile matches. In Mexico he is revered as one of the country's all-time greats, though many U.S. fans remember him for a studs-up, head-butt foul on Cobi Jones that earned him a red card at the 2002 World Cup.

Marquez debuted in Mexico's top-flight league in 1996 with Atlas and moved to AS Monaco of France's Ligue 1 three years later. In 2003, Marquez joined Barcelona and spent 10 years there, helping the Catalonia superclub win Spanish league and Champions League trophies.

Advancing into his 30s, Marquez then had stints with the New York Red Bulls of Major League Soccer, Leon of Mexico and Hellas Verona in Italy's Serie A before returning to Atlas.

A longtime fixture of Mexico's national team, he led El Tri at four World Cups and has hoped to become only the third player ever to compete in five. Marquez has scored 13 goals wearing the green jersey in 158 appearances between 1997 and 2017, according to statistics published by the Mexican Football Federation.

Speaking in a briefing to reporters, a high-level Treasury Department official said the association between Marquez and Flores Hernandez went back at least 20 years and Marquez served as "an important" frontman for money laundering. Under the terms of the briefing, the official could not be named. Among the entities that the department cited were his football academy and health and rehabilitation clinics.

Marquez's children's foundation was also linked to Flores Hernandez, though it also had a number of corporate sponsors. It claimed to have provided food as well as educational and sports programs for about 1,000 low-income kids.

Vigil said cartel figures have long been drawn to football stars and musicians.

"They love football ... so they love to associate with sports figures," Vigil said. "Who else do they like? They like these 'norteno' singers, because these guys create ballads about their exploits and it adds to their legend, to the folklore."

The sanctions freeze all U.S. assets of the people and entities named and forbid U.S. citizens from doing business with them.

The Associated Press contributed to this report.