Copper prices plunged below $9,000 a ton in the biggest drop since March 2020 as worries over the impact of a worsening trade war sparked a heavy selloff in metals and mining equities.

The bellwether metal fell 6.3% to settle at $8,780 a ton in London on Friday, as losses accelerated across the industrial metals markets following Thursday’s heavy selloff. Copper traded on New York’s Comex also tumbled, on course for the biggest two-day decline since 2011. Nickel on the London Metal Exchange plunged to the lowest price since 2020.

The declines came after China’s official Xinhua News Agency reported that Beijing will retaliate with a 34% tariff on all imports from the US starting April 10. Major mining companies also plunged, with Freeport-McMoRan Inc. and Teck Resources Ltd. losing more than 10%.

LME copper fell more than 10% this week, its biggest slide since the start of the pandemic in March 2020. Comex copper was down 8.6% to $4.412 a pound at 1 pm in New York.

Aluminum fell for a 12th straight day, while nickel slumped 6.2% to settle at $14,758 a ton, the lowest since October 2020. Tin also plunged, wiping out a weekly gain driven by concerns about supply disruptions. Chinese markets were closed Friday for a public holiday.