The US, UK and EU have announced that they will restrict Russian oil and gas imports.
The move came after Russia warned it could cut off gas supplies to European countries if an oil ban were to go ahead.
What sanctions are there on Russian oil and gas?
The US has announced a complete ban on Russian oil, gas and coal imports, after Ukraine called for sanctions to be expanded.
The UK is to phase out Russian oil by the end of the year, and the EU is reducing its Russian gas imports by two-thirds.
The UK government says this allows enough time for it to find alternative supplies.
Deputy Russian Prime Minister Alexander Novak has said rejecting Russian oil would lead to "catastrophic consequences for the global market".
Oil and gas prices have already risen sharply, and if Russia were to halt exports they would rise further.
How much oil does Russia export?
Russia is the third biggest producer of oil in the world, behind the US and Saudi Arabia.
Of about five million barrels of crude oil it exports each day, more than half of that goes to Europe.
Russian imports account for 8% of total UK oil demand.
The US is less reliant, with about 3% of its imported oil coming from Russia in 2020.
Energy policy research analyst Ben McWilliams says it should be easier to find alternative suppliers for oil than for gas, because while some comes from Russia, "there's also a lot of shipments from elsewhere".
The US has been asking Saudi Arabia to increase its oil production, but it has rebuffed previous US requests to boost output in order to reduce oil prices.
Saudi Arabia is the biggest producer in Opec, the oil cartel which accounts for about 60% of the crude oil traded internationally. Because of this Opec has a key role in influencing oil prices. So far, no Opec member has agreed to any requests to boost output.
Russia is not in Opec but has been working with it since 2017 to place limits on oil production, in order to maintain earnings for producers.
The US is also looking at relaxing Venezuela's oil sanctions. It used to be a key US oil supplier, but recently Venezuela has largely been selling its oil to China.
What would happen if Russian gas stopped flowing into Western Europe?
Heating prices - which are already high - would increase even more.
Russian gas accounts for about 40% of the EU's natural gas imports.
If this dried up, Italy and Germany would be especially vulnerable.
