As the new coronavirus has swept across the world, governments have put the squeeze on trade in the vital medical supplies needed to fight it.

The U.S. this week invoked a Korean War-era law and ordered 3M Co. to halt exports of its protective masks to Canada and Latin America and prioritize sales to the federal government. Meanwhile, German officials said a shipment of face masks ordered from a U.S. manufacturer and destined for Germany was seized at Bangkok airport and diverted to the U.S.

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