The U.S. Chamber of Commerce said it was the victim of fraud Monday after a group claiming to represent the organization said the Chamber had switched its position on climate change.

A Chamber of Commerce spokesman said he broke up a group holding a fake press briefing at the National Press Club stating that the Chamber now supports the science of climate change and stringent legislation to curb greenhouse gas emissions. He said the group used a chamber emblem at the briefing.

The spokesman said the Chamber hasn't questioned the science of climate change but rather some of the policies that Democratic leaders are pursuing to cut greenhouse gases. The Chamber is investigating those responsible for the event.

"The irresponsible, and possibly illegal, tactics are a foolish distraction from the serious effort by our nation to reduce greenhouse gases." Senior Vice President for Communications and Strategy Thomas Collamore said later in a statement. "The U.S. Chamber believes that strong climate legislation is not incompatible with the goals of improving our economy and creating jobs. We continuously seek opportunities to engage in a constructive dialogue to achieve these goals," he said in a statement.

An individual who called himself Andy Bichlbaum contacted Dow Jones Newswires said his group, the "Yes Men," claimed responsibility for the fabrication.

"We're trying to get information about climate front-and-center in the media and put pressure on big business to do the right thing," he said. The stunt comes as the Yes Men launch a movie of the group's escapades. Previous stunts have targeted Exxon Mobil Corp. (XOM) and Dow Chemical Co. (DOW).

The hoax comes after several prominent businesses left the Chamber in recent weeks, saying the organization doesn't represent their views on climate legislation. Environmental groups have highlighted the departures in a press campaign as part of an effort to pressure the Chamber to change its opposition to climate legislation under consideration in Congress.

The fraudulent press briefing was reported as news by several organizations, including Reuters, CNBC and Fox Business. Reuters later issued a correction on the story. Fox Business is a unit of News Corp. (NWS, NWSA), which owns Dow Jones & Company, publisher of this newswire.

A Fox Business spokeswoman said the agency corrected the report within a minute of announcing the fraudulent event. Donna Leinwand, president of the National Press Club, said officials challenged the legitimacy of the event about an hour before it started, and a Chamber official disbanded the briefing within a few minutes.

The group, whose fraudulent Web site was registered under "Support and Commitment, Inc.," is believed to be behind other similar hoaxes.

The group also sent out a fraudulent invitation for the fake event Monday. Quoting a nonexistent press officer named "Hingo Sembra," the invitation said: "We believe that strong climate legislation is the best way to ensure American innovation, create jobs, and make sure the U.S. and the world are on track to reduce global carbon emissions, and to provide for the needs of the American business community for generations to come."

An "Erica Avidus," listed as a contact on the release, didn't return calls. The root of "Avidus" in Latin refers to greed. Telephone numbers listed in the fake invitation and for the registered owner of the Web site weren't listed in directory assistance. An email to the contact wasn't returned, and the registered street address for the Web site owner doesn't exist.

On the Web site, Chamber President Thomas Donohue is fraudulently quoted in a prepared speech. "We at the Chamber have tried to keep climate science from interfering with business," the fraudulent remarks said. "But without a stable climate, there will be no business. We need business more than we need relentlessly higher returns."

A Chamber spokesman said the organization hadn't yet determined whether it would turn its investigation over to the authorities, but noted that there was possible wire fraud and unauthorized use of the Chamber's trademark.

Yes Men's "Bichlbaum" said the risk for prosecution, "is a risk worth taking."

He said although lawyers advised against such hoaxes, warning of the legal implications of fraud, others said: "You've got right on your side and in the court of public opinion you'll win."

"We do invite the Chamber to ask those questions, it would invite more attention," he said.

-By Ian Talley, Dow Jones Newswires, 202-862-9285; ian.talley@dowjones.com