[Here’s the state’s page with links to containment guidelines for various situations.]

The new measures came in the midst of a fast-moving pandemic, which has killed thousands around the globe.

Federal officials on Sunday recommended that all gatherings of 50 or more people nationwide be canceled or postponed for eight weeks.

[Read the latest updates from around the world here.]

In California, as of Sunday afternoon, Mr. Newsom said there had been six deaths linked to the virus. The state had 419 confirmed cases, according to data compiled by The New York Times.

Roughly 8,300 tests for the virus had been administered in California, Mr. Newsom said, and health officials were working to ramp up that number.

He highlighted a pilot partnership with Verily, a subsidiary of Google’s parent company, to help figure out which people should be tested, and to direct them to mobile testing sites around the Bay Area.