Beijing:China and the United States on Thursday promised closer cooperation on climate change and North Korea, although China warned the US not to take sides on its maritime disputes with Asian neighbors. The two sides discussed cyberhacking but announced no progress toward resolving US accusations of widespread Chinese theft of government and corporate secrets. At the conclusion of an annual high-level dialogue, US Secretary of State John Kerry said the two sides discussed ways to persuade North Korea to give up nuclear weapons. We both understand that there's more we can do in order to bring North Korea into compliance with its obligations to denuclearize, he said. The US has long pushed for China to use its status as North Korea's only major ally, and a crucial source of fuel and food, to pressure Pyongyang to give up its nuclear capabilities. The US and Western leaders saw President Xi Jinping's visit to South Korea last week as a positive sign. Yang Jiechi, China's top diplomat, said it was important to maintain restraint in dealing with North Korea and said the two sides could do more things to relax the situation.