Russia is under sanctions by its major trading partners such as the EU and the UK after the invasion of Ukraine.
But could China help out Russia economically?
Will sanctions on Russia affect trade?
China says it will "continue to have normal trade co-operation" with Russia.
But some Russian banks have now been banned from the Swift international payment system. This is used around the world for financial transactions, and is likely to make paying for its exports more difficult.
As a result, China has recently had to cut back some of its purchases from Russia because traders have struggled to arrange financing.
In recent years, both countries have been making efforts to develop their own alternative payment systems to reduce their reliance on dollar-based systems like Swift.
Russia has its System for Transfer of Financial Messages (STFM) while China has the Cross-Border Interbank Payment System (CIPS), and these operate in their own currencies.
One study published by the Carnegie Moscow Center argues that these homegrown payment systems are "not an alternative to Swift".
