In Copenhagen, environment ministers are working to bridge the gap between wealthy and developing countries before the deadline for a global agreement on addressing climate change. Yvo de Boer, the head of the UN Climate Change Secretariat, pointed out tensions between China and the United States and expressed hope that all nations would be willing to increase their commitments in the negotiations. The ministers were engaged in informal discussions on a one-day break during the December 7-18 meeting involving 190 nations. This meeting will end in a summit of world leaders on Thursday and Friday, with US President Barack Obama in attendance. Danish Minister Connie Hedegaard informed reporters that despite numerous challenges and unsolved problems, there is a political will among ministers as they begin to arrive. The discussions bring together representatives from both wealthy and impoverished nations who have been debating responsibility for emissions reductions, the necessary extent of these reductions, and who should provide funding for them. Countries such as China and India are calling for the industrialized nations to make more significant reductions in greenhouse gas emissions and provide financial assistance to help poorer countries transition to more environmentally friendly practices and adapt to the effects of climate change. Indian Environment Minister Jairam Ramesh expressed optimism about the possibility of reaching a fair agreement in Copenhagen if there is trust, courage, and conviction among all parties. Wealthier nations argue that developing countries need to limit their carbon emissions to avoid dangerous levels of global warming. China is eager to finalize a solid agreement before Premier Wen Jiabao attends the summit with other world leaders. Senior Chinese envoy Su Wei stated on Saturday that he believes the leaders are coming to celebrate the positive outcome of the talks. Following this, South African Nobel Peace Prize winner Archbishop Desmond Tutu delivered thousands of signatures to the UN's de Boer, urging for climate action. In addition, an afternoon church service was scheduled at Copenhagen's Cathedral with a sermon by Archbishop of Canterbury Rowan Williams, attended by Danish royalty, and followed by a "bell ringing for the climate" in churches globally. According to a police spokesman, all but 13 of the nearly 1,000 individuals detained after a peaceful march on Saturday have been released. Despite the march being largely peaceful, violence broke out in the evening as some demonstrators vandalized property and set fire to cars. Some individuals who were detained claimed that they were unjustly held and mistreated by the police. Hana Nelson, a 24-year-old student from Halifax, Canada, stated, "They arrested us without cause. We were all peaceful." Nelson was eventually released without any charges.