A close ally of President Vladimir V. Putin of Russia met with China’s top leader, Xi Jinping, on Wednesday, a sign of the countries’ alignment amid Russia’s deepening international isolation.
Dmitri A. Medvedev, the former Russian president and prime minister, held a previously unannounced meeting with Mr. Xi in Beijing as Chinese and Russian naval ships began weeklong joint exercises in the East China Sea.
China has remained a significant, if largely silent, counterweight to the international censure of Mr. Putin. Russia has backed China’s claim over the island democracy of Taiwan, and trade between the two countries has increased as the United States and Europe have imposed sanctions and sought to choke off Russia’s economy.
Still, China has appeared reluctant to openly support Russia’s war effort in Ukraine, staying away from supplying arms or actively aiding Moscow’s efforts to skirt Western sanctions.
“Russia has tried to portray a better relationship with China than reality affords,” said Yun Sun, director of the China program at the Washington-based Stimson Center. “It shows how desperate they are and how China has not been as helpful as they’d like.”
Mr. Medvedev is a longtime Putin ally and has emerged as one of the government’s most hawkish voices advocating a hard line against Ukraine and its allies, primarily the United States. He is the deputy chairman of Mr. Putin’s security council and the head of Mr. Putin’s ruling party, United Russia.
Mr. Medvedev said in a brief video address after the meeting with Mr. Xi that he had discussed “cooperation between the two ruling parties” as well as “our strategic partnership in all spheres.”
For the Kremlin, the meeting served as useful counterprogramming hours before President Volodymyr Zelensky of Ukraine was scheduled to meet with President Biden. On Monday, Mr. Putin himself met with President Aleksandr G. Lukashenko of Belarus to discuss deepening economic and military ties with the close Russian ally.
In Beijing, Mr. Xi told Mr. Medvedev that relations between the two countries had “stood the test of international changes” and that their partnership was a “long-term strategic choice made by both sides,” according to the state broadcaster, China Central Television.
Mr. Xi emphasized that China actively supported the idea of holding peace talks over Ukraine, and said that China hoped that “relevant parties would exercise rational restraint” in the crisis.
The military drills, annual naval exercises held since 2012, cap a year that began with China and Russia pledging a “no limits” partnership on the eve of Russia’s invasion of Ukraine. Since then, Beijing has kept funds flowing to buy Russian oil as the United States and Europe impose sanctions. Though Mr. Putin referred to “questions and concerns” raised by Mr. Xi when they met in person in September, the countries’ economic and military ties have continued to deepen.
The exercises, involving a Russian-guided missile cruiser and Chinese destroyers, will include joint air defense and anti-submarine activities to improve coordination and cooperation between the two navies, according to statements from both countries’ foreign ministries.
Military cooperation between the two countries has been scaling up over the past decade even though Russia and China are not formal allies that would come to each other’s defense in war. Both view the United States as their chief security threat and want to establish an alternative to the international order led by Europe and the United States.
During a discussion in Moscow in October, Mr. Putin lauded the state of relations with China, saying they had “reached an unprecedented level of openness, mutual trust and effectiveness in recent decades.”
Zixu Wang contributed reporting.