Russian oil exporters are predicted to take in $153 billion this year, according to the Kyiv institute. Fossil fuels are the single largest source of budget revenue. The imports support Russia’s ruble currency and help Russia to buy goods from other countries, including weapons and parts for them.

U .S. and Chinese officials may be able to settle many of their differences to reach a trade deal and avert punishing tariffs, but they remain far apart on one issue: the U.S. demand that China stop purchasing oil from Iran and Russia.

Analysts say the flow of oil between China and Russia is essential for both countries, and China is unlikely to stop buying from its biggest provider of crude.