Top diplomats from the U.S. and China met in the coastal north China city of Tianjin on Monday. Chinese Foreign Ministry spokesperson Zhao Lijian said the two sides have exchanged views on issues of common concern such as the Iranian nuclear issue, the Korean nuclear issue and climate change. Zhao said China also raised its concern on issues related to the South China Sea, Taiwan and Hong Kong. China urged the U.S. to change its wrong behavior, and stop challenging China's bottom line.