Russian President Vladimir Putin yesterday congratulated Xi Jinping on officially becoming China's president, hailing the two sides' "strategic partnership" and calling for even closer ties.
Leaders of Japan and the Philippines, which have territorial disputes with China, also offered their congratulations.
Across the strait, Taiwan's Mainland Affairs Council also congratulated Xi on becoming "the mainland's new leader", and called for continuous cross-strait efforts to promote happiness and well-being for the people on both sides under the principle of "shelving disputes in order to create a win-win situation across the strait".
Putin told Xi, who is expected in Moscow later this month as part of his first foreign trip as president, that he looked forward to meeting the Chinese leader, the Kremlin said.
In a telephone conversation, Putin "expressed satisfaction with the development of the strategic partnership between Russia and China", the Kremlin said.
Putin also "underscored [Russia's] interest in expanding co-operation in all areas, [including] on the international arena". Xi said he always made Russia the priority of China's foreign relations. He said Beijing would work with Moscow to further bilateral co-operation in all areas.
In Tokyo, Japan's Chief Cabinet Secretary Yoshihide Suga told a regular briefing that Prime Minister Shinzo Abe sent a congratulatory message to Xi.
"The relationship with China is one of the most important international relationships for Japan," Suga said, adding that Japan wanted to work with Xi in the spirit of a "mutually beneficial relationship based on common strategic interests".
While Japan would not budge on its claim over Tokyo-administered islands in the East China Sea, called the Senkakus by Japan and the Diaoyus by China, Tokyo wished to work with Xi from a big-picture point of view, he added.
"We have always kept our door open for dialogue with China," Suga said.
In Manila, Philippine presidential spokesman Edwin Lacierda said that the Aquino administration extended its sincere congratulations to Xi, Xinhua reported.
"We will seek to help build a climate of mutual trust and co-operation to enhance stability in our region," he said.