China and Russia pledged to deepen their relationship and oppose "power politics" amid tough negotiations with President Donald Trump on trade and war.

Chinese President Xi Jinping told Russia's Vladimir Putin on Thursday their two countries should be "friends of steel", as they pledged to raise cooperation to a new level and "decisively" counter the influence of the United States.

The Trump administration has said it wants to pull apart Russia and China, but the two countries need each other too much.