Xi Jinping promised to strengthen coordination with Russia at a Kremlin summit with President Vladimir Putin on the Chinese leader's first visit to Moscow since the beginning of Russia's assault on Ukraine.
Both nations seek allies to counteract Western power and the two are expected to sign a raft of economic cooperation agreements.
Mr. Putin called the talks "meaningful and frank" and said that Russia, which has been largely cut out of European markets because of sanctions, would be able to meet China's "growing demand" for energy.
"I propose strengthening our coordination and cooperation," Mr. Xi said between two rounds of talks in the Kremlin in footage shown on Russian state television.
Mr. Putin said he was "convinced that our multi-level mutually beneficial cooperation will strengthen further".
Neither leader made any mention of the conflict in Ukraine, although the Kremlin said they would discuss China's proposal to stop the fighting.
The Chinese leader's Moscow visit has been viewed as a boost for Mr. Putin, who is subject to an International Criminal Court warrant over accusations of unlawfully deporting Ukrainian children.
Mr. Xi earlier met with Prime Minister Mikhail Mishustin and hailed Russia and China as "great neighbouring powers" on the second day of his visit to Russia.
Beijing and Moscow's trade ties have boomed since Russia's Ukraine offensive, linking the nations more closely and raising worries in Western capitals over how far the ties will go.
On Monday, Mr. Xi and Mr. Putin held four and a half hours of talks, calling each other "dear friend."
In a rare move, Mr. Putin escorted Mr. Xi to his car after the talks, and the two were seen smiling together.
During the meeting on Monday, the Russian leader said he was open to talks on Ukraine and praised Beijing's 12-point position paper on the conflict, which includes a call for dialogue and respect for all countries' territorial sovereignty.
Another key focus for discussions will be energy ties.
Ahead of Tuesday's summit, Russian gas giant Gazprom said that supplies through the Power of Siberia pipeline to China had reached a daily record on Monday.
Russia also announced that it was extending until the end of June oil production cuts of 5,00,000 barrels per day, a response to Western sanctions that was due to expire at the end of March.
Mr. Xi's three-day visit began a day after Mr. Putin travelled to Mariupol in eastern Ukraine, his first trip to territory captured from Kyiv since the start of the assault in February 2022.
China has sought to portray itself as a neutral party in the Ukraine conflict, but Washington has said Beijing's moves could be a "stalling tactic" to help Moscow.
U.S. Secretary of State Antony Blinken said Mr. Xi's Moscow visit "suggests that China feels no responsibility to hold the president accountable for the atrocities committed to Ukraine".
"And instead of even condemning, it would rather provide diplomatic cover for Russia to continue to commit those great crimes," he added.
The U.S. has accused Beijing of mulling arms exports to Moscow, claims China has vociferously denied.
Ukrainian President Volodymyr Zelensky has said he would welcome talks with Mr. Xi, though there has been no indication from Beijing of any such plans.
Moscow and Beijing have over the past years ramped up cooperation, both driven by a desire to counterbalance U.S. global dominance.
While Beijing has called for an "impartial" mediation in the Ukraine conflict, Western countries have argued that China's proposals are heavy on grand principles but light on practical solutions.
The U.S. said last week that China's proposals would simply consolidate "Russian conquest" and allow the Kremlin to prepare a fresh offensive.
China and Russia have often worked in lockstep at the UN Security Council, using their veto power as permanent council members to counter the West.
Russia's assault on Ukraine has also deepened fears among Western powers that China could one day try to take control of the self-ruled island of Taiwan, which Beijing sees as part of its territory.