China firmly supports the efforts of Mr. Putin “to unite and lead the Russian people in overcoming difficulties” and “further establish Russia’s status as a major power on the international stage,” Mr. Wang said.

Mr. Lavrov congratulated Mr. Xi on his “utter success” at a recently concluded Communist Party congress in Beijing, according to the Chinese readout. In addition to securing his third term, Mr. Xi used the congress to stack the party’s top leadership with his allies and protégés, paving the way for him to rule China essentially unchallenged.

Among the loyalists promoted at the meeting was Mr. Wang, who was named to the party’s ruling Politburo, making him the top foreign-affairs official for both the party as well as the government. 

Though Beijing and Moscow aren’t formal diplomatic allies, the Chinese leader has been Mr. Putin’s most powerful supporter. The two spoke at a regional summit in Uzbekistan in September, in the first face-to-face meeting between the leaders since the start of the Ukraine war and Mr. Xi’s first trip abroad since Covid-19 began spreading significantly in the Chinese city of Wuhan in early 2020. 

Mr. Putin acknowledged Chinese concerns about Ukraine during that meeting, in what some political analysts took as a sign that Beijing was trying to distance itself from Moscow’s invasion of its neighbor.

Thursday’s call between the foreign ministers was likely driven by domestic concerns in both countries, according to Yun Sun, a China expert at the Stimson Center in Washington, D.C.

“Xi is in need of foreign validation of the result of the Party Congress. Putin is being challenged at home due to the war in Ukraine,” she said. “The call is more a demonstration of mutual support by the two leaders.” 

While Western powers continue to excoriate Mr. Putin for his actions in Ukraine, many countries in the global south, led by Beijing, have continued to stand behind the Russian leader.

China has expressed concerns about the war and taken steps to avoid Western sanctions, saying it hasn’t provided weapons to Russia. But Beijing has also supported the Russian economy, including with oil purchases, and said repeatedly that Mr. Putin has understandable concerns in Ukraine.

Mr. Lavrov informed his Chinese counterpart about the course of what the Kremlin calls its special military operation in Ukraine, a euphemism for the war, and “expressed gratitude to the Chinese side for supporting Russia’s position in favor of a fair settlement,” according to a Russian Foreign Ministry readout of the call.

Speaking at a policy conference in Moscow, also on Thursday, Mr. Putin said, “China understands very well what the desire of the West to advance the infrastructure of the NATO bloc to our borders means for Russia,” adding, however, that he respected Beijing’s position of calling for a peaceful solution to the crisis.

Mr. Putin called Mr. Xi a “close friend,” describing Russian-Chinese relations as having reached “an absolutely unprecedented level of openness, mutual trust and efficiency.” The Russian leader highlighted that the two countries are now working together in all spheres, from the military and technical to the economic and cultural arenas.  

In their call, Messrs. Wang and Lavrov agreed to step up coordination on the United Nations Security Council and on processes in the Asia-Pacific region, the Russian readout said.

The Chinese readout mentioned Ukraine only briefly, saying the two men discussed it along with other “international and regional issues of common concern.”

Close ties between Messrs. Xi and Putin have caused consternation in Washington. U.S. Secretary of Defense

Lloyd Austin

named both countries while laying out the Biden administration’s new defense strategy on Thursday. 

Washington sees Moscow as an acute threat because of the invasion of Ukraine, Mr. Austin said, but it regards Beijing as the bigger challenge, because China is “the only competitor out there with both the intent to reshape the international order, and increasingly the power to do so.”

Write to Josh Chin at Josh.Chin@wsj.com, Ann M. Simmons at ann.simmons@wsj.com and Wenxin Fan at wenxin.fan@wsj.com