Prime Minister Mikhail Mishustin - the highest ranking Russian official to visit Beijing since Moscow sent thousands of its troops to Ukraine in February 2022 - held talks with Chinese Premier Li Qiang and was due to meet with President Xi Jinping.
With the war in Ukraine in its second year and Russia increasingly feeling the weight of Western sanctions, Moscow is leaning on Beijing for support, far more than China on Russia, feeding on Chinese demand for oil and gas.
The pressure from the West has shown no sign of easing, with the Group of Seven nations' weekend declarations singling both countries out on a plethora of issues including Ukraine.
"Today, relations between Russia and China are at an unprecedented high level," Mishustin told Li in their meeting.
"They are characterised by mutual respect of each other's interests, the desire to jointly respond to challenges, which is associated with increased turbulence in the international arena and the pattern of sensational pressure from the collective West," he said.
"As our Chinese friends say, unity makes it possible to move mountains."
The memorandums of understanding signed included an agreement to deepen investment cooperation in trade services, a pact on export of agricultural products to China, and another on sports cooperation.
Russia's energy shipments to China are projected to rise 40 per cent this year, and the two countries are discussing technological equipment supplies to Russia, Interfax news agency reported.
"With sanctions against Russia providing new opportunities for China, it is hardly surprising that China would be happy to engage actively, if not proactively with Russia economically, as long as whatever relationships they forge will not trigger secondary sanctions against China," said Steve Tsang, director of The School of Oriental and African Studies (SOAS) China Institute in London.
"China's policy towards the war in Ukraine is one of "declaring neutrality, supporting Putin and paying no price", and the visit reaffirms it, particularly the support Putin element," said Tsang.
Xi visited Russia in March and held talks with "dear friend" President Vladimir Putin, after committing to a "no limits" partnership just before the 2022 Russia attack on Ukraine, which Moscow calls a "special military operation."
Beijing has rejected Western attempts to link its partnership with Moscow to Ukraine, insisting their relationship does not violate international norms, China has the right to collaborate with who it chooses, and their cooperation is not targeted at any third countries.
"China is willing to work with Russia to implement the joint cooperation between the two countries, and promoting pragmatic cooperation in various fields can take it to a new level," Li told Mishustin.
Deepening of ties with China is a strategic course for Moscow, said the secretary of Russia's Security Council Nikolai Patrushev, who held talks on Monday with Chen Wenqing, member of the Chinese Communist Party's Politburo who oversees police, legal affairs and intelligence.
Beijing has refrained from openly denouncing Russia's invasion. But since February, Xi has promoted a peace plan, which has been met with scepticism from the West and cautiously welcomed by Kyiv.
Last week, China's special representative for Eurasian affairs Li Hui visited Ukraine and met with President Volodymyr Zelenskiy in a European tour that Beijing billed as its effort to promote peace talks and a political settlement of the crisis.
Li Hui is scheduled to visit Russia on Friday.
