When President Xi Jinping held talks with UN secretary-general Ban Ki-moon in Beijing on Wednesday he urged the United Nations to be "fair and just", indicating that Beijing would like to play a more prominent role in international affairs.
Xi and Ban discussed the conflict in Syria and North Korea's nuclear programme, but Xi also outlined China's expectations of the UN, calling on its members to scrap the "zero-sum mindset".
The UN should "uphold the principles of impartiality and righteousness" and "speak in a fair manner", Xinhua quoted Xi as saying.
In remarks that showed China's growing assertiveness in foreign policy, Xi said China bore heavy responsibilities as a permanent member of the UN Security Council, but the nation "has the capability" to fulfil the mission.
China would step up its efforts to promote peaceful settlement of international disputes, and work with other nations to tackle climate change, Xi added.
Observers said Xi's remarks signalled a shift in China's diplomatic tactics, with his predecessors having always stressed that China was still a developing country and was reluctant to take on more responsibilities.
"The remarks indicated that China does not want to be the supporting actor in global affairs, and it wants to be in leading positions," said Zhao Junjie , an international relations specialist at the Chinese Academy of Social Sciences.
China has been calling for a multipolar world order, arguing that the existing international governance structure is dominated by major powers. Beijing also showed frustration when it was condemned, along with Russia, last year for vetoing UN Security Council resolutions against Syria.
"Beijing believes its voice and that of the developing nations are not heard enough in the UN and wants it to reform," Zhao said.
Jin Canrong , a specialist in international relations at Renmin University, said China wanted a bigger voice in the UN because it had more power and money.
"Xi has a more straightforward personality, and he feels confident and proactive in terms of foreign policy," he said. "China's foreign policy used to be reactive but now it's becoming more proactive - regionally as well as globally."
Mathieu Duchâtel, head of the China and International Peace and Security Project at the Stockholm International Peace Research Institute, said Xi's remarks were consistent with his heightened focus on foreign policy.
"China prioritises making sure the UN Security Council does not function as an instrument for the US and European countries to promote their own interests," he said.
Duchâtel said China wanted the UN to be the main player in international affairs, to balance the US-led North Atlantic Treaty Organisation.