Chevron is scrambling to deal with an elaborate lampoon of a major advertising campaign that the company introduced on Monday. The identity of the pranksters is not known.

Chevron announced the campaign to reporters on Monday morning in e-mails, which were sent after the publication of an article about the ads in the Monday editions of The Wall Street Journal. There was also a news release about the campaign posted to a section of the Chevron Web site.

The campaign, by McGarryBowen in New York, carries the theme “We agree.” The ads seek to address critics of energy companies by affirming statements like “Oil companies should support the communities they’re part of” and “Oil companies should put their profits to good use.” A section of the Chevron Web site is also devoted to the campaign.

However, hours before the e-mails were sent, e-mails designed to resemble Chevron corporate missives also went out. They cited a different Web address, chevron-weagree.com, and included a link to what seemed to be an authentic news release on the official Chevron site.

The spoof news release carries the headline “Radical Chevron Ad Campaign Highlights Victims,” compared with the actual Chevron news release headline, “Chevron Launches New Global Advertising Campaign: ‘We Agree.’”

The spoof news release echoed language from the actual news release and included concocted quotations from actual Chevron executives. The main difference between the lampoon and the real was that the fake release described the ads as addressing environmental issues in which Chevron is embroiled, including a dispute in Ecuador over oil pollution; the real ads do not directly address those matters.

At least one news outlet, the Web site of Fast Company magazine, was fooled by the prank.

The fake e-mail was followed by another, purporting to reproduce a news release that Chevron supposedly posted on the Business Wire service. It described how “a group of environmentalists cyber-posing as Chevron officials illegally spoofed Chevron’s just-launched ‘We Agree’ advertising campaign, confusing reporters.”

The second fake release, like the first, also attributed made-up quotes to real Chevron executives.

Morgan Crinklaw, a spokesman for Chevron in San Ramon, Calif., said the company was “taking down the Web sites that purport to be Chevron’s.”

“We expected something like this would be done,” he said in a phone interview on Monday afternoon, because “there are activist groups whose sole focus is attacking Chevron and not engaging in rational conversations on energy issues.”

Mr. Crinklaw also forwarded by e-mail a statement from Chevron that called the lampoon “rhetoric and stunts” and condemned the “fake press release” and “counterfeit Web site, which are not affiliated with Chevron.”

The e-mail asked reporters to contact the company “to ensure the accuracy of the information they have received” about the campaign.

Asked who might have been behind the spoof, Mr. Crinklaw replied: “I don’t want to speculate. I don’t know the answer.”

Fast Company, in updating the article on its Web site, said that the pranksters known as the Yes Men were behind the hoax but did not describe what led to that conclusion. That information could not be independently verified. The Yes Men are known for mocking big business and what they perceive to be corporate misdeeds.

Some environmental organizations welcomed the lampoon, whatever its provenance.

“The spoof is a direct consequence of Chevron’s trying to fool people into thinking it is an environmentally conscious when the company is responsible for the extensive contamination found in Ecuador’s rain forest and in other places as well,” Karen Hinton, a spokeswoman for the Ecuadorian plaintiffs suing Chevron, said in an e-mail on Monday afternoon.

Earlier, before the spoof became widely known, Ms. Hinton sent an e-mail in which the plaintiffs criticized the actual Chevron campaign as “greenwashing.”