Russia last year overtook Saudi Arabia to become the largest supplier of oil to China, Reuters reported, citing Chinese import data.
Russia supplied 107 million tons of oil to China in 2023, the equivalent of 2.1 million barrels a day, the agency said.
Saudi Arabia, China’s top supplier for many years, delivered 86 million tons, a 2 percent drop compared with the previous year.
China is the world's largest net importer of oil, having overtaken the United States in 2017.
Western sanctions imposed on Russia for its February 2022 invasion of Ukraine has upended global trade, including the shipment of fossil fuels.
Europe, the biggest buyer of Russian oil prior to the war, banned imports of the fossil fuel, and, along with the United States, imposed a $60 price cap on Russian oil shipped using EU and U.S. services, such as transportation insurance.
The price cap was designed to keep Russian oil flowing to global markets to prevent a price spike while also limiting Russian budget revenue. Oil exports account for more than 30 percent of Russian federal budget revenues.
The Western oil ban forced Russia to pivot east to sell its oil. China and India willingly snapped up Russian crude sold at a discount to global prices.
Russia also became the biggest supplier of oil to India last year, accounting for nearly a third of its import demand.
Meanwhile, to offset lower sales to China, Saudi Arabia began shipping more of its oil to Western markets.
Russia and Saudi Arabia are the second- and third-largest oil producers in the world, trailing the United States.
Increasing U.S. oil production has offset attempts by Russia and Saudi Arabia to prop up the price of the fossil fuel via output cuts.
The European crude benchmark Brent is down nearly 8 percent over the past year to $77.75 a barrel.