Xi Jinping prepares to welcome Vladimir Putin to China, four days after hosting Donald Trump

China's deep relationship with Russia remains a continuing cause for concern in the west, particularly since Moscow launched its invasion of Ukraine

Xi Jinping and Vladimir Putin exchanged congratulatory letters" on Sunday ahead of the Russian president's visit to Beijing this week, four days since Donald Trump left China after a high-stakes summit.

Xi, China's leader, said bilateral cooperation between Russia and China had continuously deepened and solidified", with this year marking the 30th anniversary of the two countries' strategic partnership, according to Chinese state media.