 Exxon Mobil Corp, a longtime opponent of mandatory regulations to combat climate change, met with US environmental groups last month to discuss how the oil behemoth might respond to global warming. This move was the latest hint that the world's biggest public company could be open to shifting its position of opposing mandatory caps on emissions of heat-trapping gases. Exxon organised an exclusive meeting with representatives from groups, including Washington environmental research group Worldwatch Institute and New York-based the Interfaith Centre on Corporate Responsibility, at meetings in Virginia to discuss climate change and human rights. Exxon spokesman Mark Boudreaux confirmed the company organised the meeting, but said what transpired was confidential. Earlier this week the company said it is meeting in separate talks with representatives from about 20 companies to discuss potential US policy options on reducing heat-trapping emissions. Environmentalists were cautiously optimistic that all the talks could indicate that the company, which had long avoided meetings with nonprofit groups on global warming and dismissed investments in emissions-reducing sources of energy like solar power, could be considering a policy shift. "Exxon could be reading the political tea leaves that emissions controls could be coming, but it has yet to agree to anything in which it would have to take mandatory action on climate change," said Gary Cook, the director of the US Climate Action Network. Since Democrats won control of Congress in November, US energy companies have been nervously watching which route the United States may take on future regulations of carbon dioxide and other heat-trapping gases scientists link to global warming. On Friday US Senators John McCain, an Arizona Republican, and Joe Lieberman, a Connecticut independent, reintroduced a bill on capping emissions that failed previously. It supports development of a cap and trade system that rewards companies that cuts emissions under set limits and penalises ones that do not. President George W Bush has opposed mandatory emissions cuts such as those required by the international Kyoto Protocol. He withdrew the United States, the world's top carbon emitter, from the Kyoto pact early in his first term. The Exxon meetings with other companies are expected to generate a report this fall, furnishing information on policy options to legislators on how to reduce emissions. For years Exxon has struggled with climate policy. It had touted reductions of heat-trapping emissions at refineries while at the same time funding groups like the Competitive Enterprise Institute that question global warming. Exxon also said this week it has stopped funding CEI and about five other groups in 2006. It said the other groups will be released in the spring. "We're winning," said Kert Davies a Washington based researcher at Greenpeace, which along with other green groups have been urging Exxon to stop funding groups that question the global warming. But he said it was yet to be determined whether Exxon's recent climate meetings represented real change on emissions.