LOS ANGELES (AP) — Los Angeles County’s coronavirus cases are rising so fast they could average more than 4,000 a day within three weeks and leave the nation’s most populous county on the cusp of a lockdown and curfew, a public health official said Wednesday.

The county announced new restrictions on businesses that go further than statewide guidelines put in place this week after Gov. Gavin Newsom said he was pulling the “emergency brake” on reopening the economy to try to control a surge.

The new regulations are effective Friday and will limit restaurants — already crippled by the virus and not able to open indoors — to half their outdoor capacity and shut them down at 10 p.m. Nonessential retailers are limited to a quarter of inside capacity.

The changes come as the county has seen its average daily cases nearly triple since Nov. 1 to close to 3,000. The daily case count Wednesday was just below 4,000.

If the county averages more than 4,000 newly reported cases a day or 1,750 hospitalizations, it would end dining and restaurants would only be able to offer food for takeout and delivery. If cases or hospitalizations reach 4,500 or 2,000, respectively, the county will go on lockdown and impose a curfew for three weeks.

“I don’t think it’s inevitable that we do get there,” said Barbara Ferrer, the director of public health. “I hope with every single bone in my body that we don’t get there.”

The county of 10 million residents has had a disproportionately large share of the state's cases and deaths. Although it accounts for a quarter of the state's 40 million residents, it has about a third of the cases and more than a third of the deaths.

Dr. Eric Topol, head of the Scripps Research Translational Institute in San Diego, said all the new restrictions rolled out or announced in the state in recent days are welcome, but they should have been done sooner when cases were first rising and he imagines LA will soon approach stay-home order levels.

“This is a bad situation,” Topol said. “It’s just slow, sluggish responsiveness, incomplete. And then we have a significant minority of people who are not willing to go along with it. We have no enforcement. If you’re indoors without a mask in a crowd it’s not like you get fined. Nothing happens to you.”

Ferrer said the restrictions were announced late Tuesday but not imposed until Friday to give businesses time to adapt. She acknowledged the county was “a little behind” in its response after talking about rising cases for three weeks.

With cases surging across the entire U.S. and Thanksgiving a week away, officials have placed new restrictions on businesses and been increasingly vocal in warnings about limiting holiday gatherings. But they've stopped short of issuing another unpopular stay-home order or forbidding Thanksgiving celebrations.

Newsom this week placed most of the state under the strictest rules for reopening, halting indoor worship services, forcing most indoor businesses to close or operate at a fraction of their capacity and keeping most schools closed to in-person instruction. He also joined governors of Oregon and Washington in urging residents not to travel and for anyone to quarantine for two weeks if arriving from another state.

He also strengthened mask-wearing requirements outdoors and said he was also evaluating the effectiveness of curfews.

Public health officers throughout the San Francisco Bay Area have discussed imposing a curfew as a way to reduce spread of the virus, but have no immediate plans for one, said Dr. Matt Willis, public health officer for Marin County.

A curfew could signal people not to socialize late into the night and encourage them to stay home, he said. But it would be difficult to enforce.

“The other principle is that we ought to allow as much freedom as we reasonably can in this period when people are making so many sacrifices," Willis said. "It’s not something to take lightly.”

The more stringent rules going into effect in Los Angeles would limit business operating hours from 6 a.m. to 10 p.m. Salons and other personal care services may only be provided by appointment and customers and staff must wear face coverings.

Dr. Linda Rosenstock, professor of medicine and health policy at the University of California, Los Angeles, said the surge had suddenly put everyone in the county at risk of encountering someone with the virus, which wasn't true even a month ago.

But the risk is much greater in the poorer parts of the city and county, where more essential workers live in denser housing and have fewer options to help limit contact with people who may be infected with the virus.

“It's a tale of two cities,” Rosenstock said. “For some, it's not having Thanksgiving together. For others, there's less flexibility in their opportunities to avoid exposure to severe community spread.”

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Associated Press writer Daisy Nguyen in Oakland contributed to this report.