Beijing: Chinese President Xi Jinping and his Russian counterpart Vladimir Putin promised ever closer cooperation on Sunday as they met for the 10th time in less than two years.
The two men, who held talks in Beijing, have increasingly stressed their shared outlooks which mirror their countries' converging trade, investment and geopolitical interests.
The two sides signed a series of agreements to step up their multi-billion-dollar natural resources collaboration.
"Together we have carefully taken care of the tree of Russian-Chinese relations," Xi told Putin at the Diaoyutai state guesthouse in Beijing.
"Now fall (autumn) has set in, it's harvest time, it's time to gather fruit," he said.
"No matter the changes on the global arena, we should stick to the chosen path to expand and strengthen our comprehensive mutually fruitful cooperation."
Russia and China have been brought together by mutual geopolitical concerns, among them wariness of the United States.
The two countries often vote as a pair on the UN Security Council, where both hold a veto, sometimes in opposition to Western powers on issues such as Syria.
Putin said that Russian-Chinese cooperation was "very important for keeping the world within the framework of international law, to make it more stable, more predictable".
"Me and you have done a lot for this and I am sure we will continue to work in this manner in the future," he added.
Moscow faces harsh Western criticism and sanctions over its seizure of Crimea and the conflict in eastern Ukraine, which could see Europe reduce its consumption of Russian gas.
Beijing also has tense relationships over territorial disputes with neighbours such as Japan, Vietnam and the Philippines.
At the same time, it is constantly on the lookout for resources to power its economic growth.
After a decade of negotiations, the countries signed a huge 30-year gas deal said to be worth USD 400 billion during a visit to China by Putin in May.
Today they stepped up the engagement, with Russia's Rosneft and China National Petroleum Corporation (CNPC), both of them petroleum giants, signing an agreement for the Chinese firm to take a 10 per cent stake in a huge Siberian energy project.
CNPC also signed deals on gas supplies and transport routes, with financial agreements also inked.
Putin is visiting China for the Asia-Pacific Economic Cooperation (APEC) summit, which starts tomorrow and will also be attended by US President Barack Obama and Japan's Prime Minister Shinzo Abe, as well as other leaders.