Putin, Xi vow to 'deepen' alliance hours after Trump re-enters the White House

"This year, I am ready, together with you, to elevate Chinese-Russian relations to a new level, to counter external uncertainties by preserving stability and resilience of Chinese-Russian relations," Xi said while addressing Putin.

The pair both vowed to back the U.N.-centered international system ahead of the 80th anniversary this year, and to defend the post-World War II global order - a nod to Putin's pursuit to reclaim Ukraine in what many have argued is an attempt to re-establish the Soviet Union. 

The Chinese and Russian leaders also reportedly "indicated a willingness to build relations with the United States on a mutually beneficial, mutually respectful basis," Kremlin foreign policy aide Yuri Ushakov told reporters, adding this will happen "if the Trump team really shows interest in this."

"It was also noted from our side that we are ready for dialogue with the new U.S. administration on the Ukrainian conflict," he added.

Neither readouts of the call issued by China or Russia directly mentioned Ukraine, though Russia highlighted that Beijing has remained a major supporter of Moscow's economy as it is the largest consumer of Russian energy resources - a major earner for Putin's war effort.

"Five years ago, we launched the Power of Siberia gas pipeline together, and today, Russia has become the leading supplier of natural gas to China," the Kremlin said in a readout.

"I believe that the past year was very good for us," Putin said. "It can be said confidently that our foreign policy ties and Russia and China's joint efforts objectively play a major stabilizing role in international affairs."