Global oil prices could rise to $200 a barrel if Europe and the United States ban imports of Russian oil, analysts at Oslo-based consultancy Rystad Energy said on Tuesday.

Oil prices jumped on Monday to their highest since 2008 on fears of a Western ban on Russian oil imports while a return of Iranian crude to the market remains far from certain.

The global Brent oil benchmark currently trades at $129 a barrel, up from about $97 before Russia’s invasion of Ukraine.

Oil prices could double from pre-conflict levels, but it wouldn’t be as bad as during the 1973 oil embargo, when oil prices tripled, said Jarand Rystad at the consultancy.

Rystad Energy analysts said the $200 estimate was based on an assumption that Western sanctions could remove about 4 million barrels per day (bpd) of Russian crude.

Russia, the world’s second-biggest oil exporter, ships about 7 million bpd of crude and oil products combined.

The United States is expected to announce a ban on Russian oil imports as soon as Tuesday, a source familiar with the matter told Reuters.

Last week Rystad had predicted that Brent crude would climb above $130 a barrel because Russian exports were to plunge by 1 million bpd as a consequence of previously announced sanctions and voluntary actions by companies.

Shell, among others, said on Tuesday that it would no longer buy Russian crude oil and would phase out its involvement in all Russian hydrocarbons.