In Copenhagen, environment ministers are working to resolve disagreements 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, emphasized tensions between China and the United States, urging all nations to increase their commitments in the negotiations. He expressed hope that in the upcoming days, all countries will urge one another to step up their efforts. The ministers were engaged in informal discussions during a one-day break in the December 7-18 meeting that includes 190 nations. This meeting will end with a summit of world leaders on Thursday and Friday, which will include US President Barack Obama. Danish Minister Connie Hedegaard informed reporters that there are still numerous challenges and unresolved issues, but there is also a visible political determination among the ministers. The discussions involve representatives from both wealthy and developing nations who have been debating over responsibilities for emissions reductions, the extent of these reductions, and who should provide funding for them. Countries like China and India are calling for the industrialized world to make more significant reductions in greenhouse gas emissions and provide financial support to developing nations in order to transition to more environmentally friendly practices and adapt to climate change. Indian Environment Minister Jairam Ramesh expressed optimism about reaching a fair agreement in Copenhagen if all parties trust each other and show courage and conviction. Developed nations argue that developing countries must also commit to reducing carbon emissions to avoid potentially catastrophic levels of global warming. China aims to finalize a solid agreement before Premier Wen Jiabao attends the summit with other world leaders. Senior Chinese envoy Su Wei indicated that the leaders are expected to arrive to celebrate the positive outcome of the talks. Archbishop Desmond Tutu delivered thousands of signatures to the UN calling for climate action, followed by a church service at Copenhagen's Cathedral led by Archbishop of Canterbury Rowan Williams and attended by Danish royalty. Police have released most of the nearly 1,000 people detained after a march on Saturday, which turned violent with demonstrators smashing windows and setting fire to cars. Some of the 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, who was released without charges, stated, "They arrested us without cause. We were all peaceful."