The signing of the long-expected China-US army dialogue mechanism and the country's upcoming agreement on the air-to-air annex to the code of conduct on military encounters represent a leap forward in the relationship between the countries, analysts have said.

However, they said the United States has to handle the South China Sea issue properly to maintain the positive momentum, and a Chinese military leader has warned Washington to be cautious in its words and deeds on key issues involving China's territorial integrity.

Central Military Commission Vice-Chairman Fan Changlong, who has just completed a visit to the US, urged Washington to reduce its military activities both in the air and in the waters of the South China Sea when meeting US government and military leaders.