For the second time in a month, the Recording Industry Association of America's (RIAA) Web site was attacked Wednesday, apparently by opponents of the industry group's efforts to shut down online music trading.

By midday Wednesday, the trade group's site was unreachable. Earlier in the day, it had been modified to contain pro-file trading messages, and even direct links to downloadable music and to file-swapping service Kazaa.

"RIAA willing to try alternative approach to music-sharing services," the defaced site's top headline temporarily read, according to one screen shot provided by a visitor to the site. Other links included "Piracy can be beneficial to the music industry," and "Where can I find information on giant monkeys."

An RIAA representative said only that there was a problem with the site and that it would be back up shortly.

The RIAA, along with the Motion Picture Association of America (MPAA), has won many critics online in its quest to shut down popular file-trading networks such as Napster. The group says Net piracy has badly cut into legitimate sales, and this week released a report that said CD sales for the first six months of 2002 were down 7 percent from 2001. Online music trading was largely responsible for undermining those sales, the group contended.

Both entertainment industry groups support a bill currently being considered in Congress that would allow copyright holders to use their own hacker-like tactics to shut down or impede file-trading networks where illegal activity was taking place.

The RIAA has previously been less active than the MPAA in pursuing individuals trading files online, focusing instead on lawsuits against companies involved. However, the organization has stepped up its activities in recent weeks, asking Verizon Communications for personal information about a subscriber who the trade group alleges has been involved in substantial illegal file distribution.

Verizon initially balked, asking that a court rule on the need to provide the information.

The trade group also sued a group of Internet backbone providers, asking that they block U.S. access to a Chinese site, Listen4ever.com, that was providing access to large amounts of illegally downloadable music. The site went offline just days after the suit was filed, and the trade group withdrew its suit.

The RIAA site suffered a malicious denial of service attack a month ago, knocking it offline for close to four days. Wednesday's more serious attack is also illegal under federal and state laws, with penalties of up to five years in prison.