MEXICO CITY (AP) — Mexican norteno singer Julio Cesar Alvarez says he knew suspected drug trafficker Raul Flores Hernandez, but only as a businessman and the owner of a club where he performed.

The U.S. Treasury Department says the singer, better known as "Julion" Alvarez, acted as a frontman and held assets for Flores Hernandez.

The department placed Alvarez on a list of people sanctioned under the Kingpin Act. The sanctions freeze all U.S. assets of the people and entities named and forbid U.S. citizens from doing business with them.

Alvarez said of Flores Hernandez: "I know him as a businessman ... and a very serious man."

He said Thursday he met Flores Hernandez after he was contracted to sing at a club he owned.

Alvarez has denied any wrong doing.