The Republican has promised to take a hard line on Washington's adversaries since taking office, threatening heavy tariffs on Beijing and warning Moscow of "big trouble" if it does not settle the Ukraine conflict.

Putin, addressing Xi as his "dear friend", said Russia and China were building ties "on the basis of friendship, mutual trust and support", despite external pressure.

"Russia and China's joint work plays an important stabilising role in international affairs," Putin said in the call.

Xi, quoted through a translator, praised their cooperation and said bilateral trade was on the rise.

Moscow and Beijing have strengthened military and trade ties since Russia sent troops into Ukraine, alarming the United States, which views both as malign actors on the world stage.

China has sought to depict itself as a neutral party amid the nearly three-year conflict.

But it remains a close political and economic partner of Moscow and has never condemned Russia's actions, leading some NATO members to brand Beijing an "enabler" of the conflict.

Both sides have made much of Xi and Putin's supposedly strong personal bond, with Xi calling the Russian leader his "best friend" and Putin lauding his "reliable partner".

burs/ach