Mr. Trump, who until this week had played down the outbreak, also invoked a wartime law that would let the government press American industry into service to make more medical supplies.

The Senate approved a separate relief package passed last week by the House that would provide paid leave, enhanced unemployment benefits and free testing as well as food and health care aid. The president quickly signed the bill, which early estimates suggest could cost hundreds of billions of dollars.

Here are the latest updates and maps of the pandemic.

In other developments:

“The Daily”: Today’s episode is about a New York suburb with a particularly large clusters of infections.

Another angle: The U.S. Navy has given officers discretion to temporarily relax guidelines on hair length to help maintain social distancing.

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