The U.S. Justice Department says it has launched an inquiry into possible price fixing in the burgeoning online music industry.

The Justice Department would not name the companies it has targeted. "The antitrust division is looking at the possibility of anticompetitive practices in the music download industry," spokeswoman Gina Talamona said Thursday.

Universal and Warner have been told by the Justice Department to expect a formal demand for information, according to the two officials, who requested anonymity because the probe was ongoing. Warner has publicly acknowledged that it was subpoenaed by Spitzer.