A worker removes an automobile exhaust pipe from a welding jig at the Gaz auto plant, operated by Gaz Group, in Nizhny Novgorod, Russia, on June 16, 2015. [Photo: CFP]

It's being reported Russia has surpassed Saudi Arabia to become China's largest supplier of oil.

In May, Russia accounted for around one-third of all of China's oil imports, reaching nearly 4 million tons.

That is a 20-percent rise from the previous month.

Observers are suggesting the rise is being driven by increasing oil deals between the two countries, as well as Russia's acceptance of the Chinese yuan in its oil deals.

At the same time, it's being reported oil supplies from Saudi Arabia have slumped by over 40-percent to some 3 million tons in May.

For more on this, CRI's Paul James earlier spoke with Professor Liu Baocheng at the University of International Business and Economics based in Beijing.