New York CNN Business  — 

Covid fears are rocking the oil market Monday as China’s planned lockdown of Shanghai raises concerns about energy demand.

US crude tumbled 7% and Brent lost 6.8% on the Covid news, giving back most of last week’s big gains. The heavy selloff comes after officials in China announced plans to lock down half of Shanghai for mass Covid-19 testing beginning Monday.

“China is the big fear factor right now,” said Michael Tran, managing director of global energy strategy at RBC Capital Markets.

For weeks, the market has been almost entirely focused on supply disruptions caused by Russia’s invasion of Ukraine.

Yet Monday’s selloff shows markets remain sensitive to shifts in energy demand, especially in China, the largest oil importer on the planet. Not only does China consume massive amounts of gasoline, jet fuel and diesel, but it’s also the largest source of energy demand growth in the world.

“To have this market firing on all cylinders, you need China. China is the biggest cylinder,” said Tran.

Shanghai, a city of about 25 million and a major hub of the Chinese economy, is set to have roughly half of its population banned from going out for four days starting Monday. The lockdown will then move to the other half of Shanghai.

“The magnitude of the selloff reflects fears that Covid lockdowns in China could spread,” Andy Lipow, president of Lipow Oil Associates, wrote in a report Monday.

Despite the losses, oil prices remain elevated as the war in Ukraine continues and the West imposes tough sanctions on Russia.

US crude settled at $105.96 a barrel. That leaves it up about 40% so far this year, including a gain of nearly 9% last week alone. Meanwhile Brent crude, the world benchmark to $112.48 a barrel Monday.

Prices at the pump remain near record highs. The national average for regular gas inched up to $4.25 a gallon Monday, according to AAA. That’s just 8 cents away from the record of $4.33 a gallon set earlier in March.