Chinese President Xi Jinping has arrived in Russia for talks focusing on expanding cooperation with Moscow just as tensions have flared up in US-China ties.<br/>' <br/>President Vladimir Putin's foreign affairs adviser, Yuri Ushakov said Moscow and Beijing will sign dozens of agreements to deepen their cooperation during Xi's two-day trip. He described the current Russia-China relations as the best in history.<br/>'<br/>Before heading to Moscow, Xi warned President Donald Trump in a call on Monday that some negative factors are hurting US- China relations, as tensions soared over the sailing of a US destroyer within the territorial seas limit of a Chinese- claimed island in the South China Sea.<br/>'<br/>Trump, Putin and Xi will attend the Group of 20 summit in Germany later this week.<br/>