China on Thursday raised the prospects of a climate deal being achieved in Copenhagen by offering to be transparent about its greenhouse gas emission targets, according to dpa. "We promise to make our actions transparent," Hu Yafei, a senior Chinese foreign ministry official, told journalists. His comments, voiced just hours before US President Barack Obama was due to arrive in the Danish capital, were a response to calls by US Secretary of State Hillary Rodham Clinton for "all of the major economies", and particularly China, to "commit to meaningful mitigation actions and stand behind them in a transparent way." Subjecting emission pledges of big polluters to an international Measurement, Reporting and Implementation (MRV) procedure is seen as a key issue in the United Nations talks due to end on Friday. Hu insisted that any international verification mechanism would have to be done on "a voluntary basis", and only in a way that would avoid foreign powers intruding on China"s sovereignty. Clinton, for her part, appeared to have softened her country"s hard-line stance on the issue by suggesting that the appropriate verification mechanism was still open to discussion. "There are many ways to achieve transparency that would be credible and acceptable," Clinton said in Copenhagen. Srinivas Krishnaswamy, an analyst at pressure group Greenpeace, welcomed the development. Asked whether the latest comments from US and Chinese officials represented a shift towards a possible compromise, Krishnaswamy said: "Very clearly yes." Both sides "have shown that they are flexible," he told the German Press Agency dpa. The US and China are the world"s biggest polluters and together account for about 40 per cent of all greenhouse gas emissions. For the Copenhagen to produce an effective deal aimed at keeping global warming in check, an agreement between the two is seen as crucial. China has vowed to curb its emissions growth by reducing its carbon dioxide (CO2) output per unit of gross domestic product (so-called "carbon intensity"). The US is offering an emission cut of 17 per cent against 2005 levels by 2020. Speaking in Copenhagen, Clinton for the first time publicly endorsed UN calls for rich nations to provide some 100 billion dollars in aid to poor nations most at risk of climate change. "The United States is prepared to work with other countries toward a goal of jointly mobilizing 100 billion a year by 2020 to address the climate change needs of developing countries," Clinton said. However, she declined to say how much her country would contribute to such a fund and insisted that the US offer hinged on a successful outcome in Copenhagen. The amount of money that rich nations are prepared to give to developing countries to cope with global warming and reduce their emissions is one of the most contentious issues on the table in Copenhagen. As some 120 world leaders took turns to address the conference, officials expressed relief at the fact that the sides had finally returned to the negotiating table after 36 hours of wrangling over procedural issues. "I would say: hold tight and mind the doors, the cable-car is moving again," said UN climate chief Yvo de Boer. Meanwhile, Danish Prime Minister Lars Lokke Rasmussen confirmed that he had given up on efforts to offer a compromise text aimed at facilitating discussions in the face of strong objections from the G77 group of developing nations. "After consultations with the G77, China and other groups ... the documentary basis for the work will be the texts reported and presented to the plenary last night," Rasmussen told delegates. Rasmussen has come under fire from various quarters, most notably from China, over his handling of the talks. The Sudanese head of the G77, for his part, rejected charges that the group was blocking discussions but lamented the loss of "two precious days of negotiations ... because of the lack of clarity on the process." With most of the controversial issues still unresolved ahead of the final day of the conference, European Union heavyweights Germany, France and Britain called for an emergency mini-summit of the world"s most powerful leaders in the evening "to help build a consensus for a global deal." And while Australian Prime Minister Kevin Rudd said he feared "a triumph of form over substance", British Prime Minister Gordon Brown said there was still hope for a "legally-binding" instrument aimed at keeping average global temperatures from rising "by no more than 2 degrees" centigrade by 2050.