The “red zone”, in comparison, could see a second stay-at-home order imposed across Los Angeles to stop Covid-19’s spread.
Mr Garcetti’s comments suggest the mayor could consider stricter measures than those imposed across the state on Monday, which see some businesses ordered shut by governor Newsom.
The order sees bars, restaurants, gyms, salons and religious centres now shut down across the state.
“Covid-19 is not going away anytime soon, until there is a vaccine and or an effective therapy,” said Mr Newsom.
“Limit your mixing with people outside of your household. It’s just common sense, but the data suggests not everyone is practising common sense.”
Religious groups and businesses organisations, who complied with California’s lockdown in March, have condemned the new closures.
Authorities in Los Angeles have warned that tougher lockdown measures could be introduced as the Covid-19 threat increases across California.
Mayor Eric Garcetti said stricter lockdown measures were possible under “emergency” conditions.
“We’ve never had as many people infected or infectious,” said Mr Garcetti, as more than 2,500 coronavirus cases and 13 deaths were documented in Los Angeles County on Monday.
It could see the highest threat level, or the “red zone”, actioned under a colour-coded warning system adopted earlier this month.
“Red is when everything shuts down again – everything, to our strictest level. And I do want to warn people that we’re close to that,” said Mr Garcetti.
Under the second-highest Covid-19 threat level known as “orange”, Angelenos were warned last week to avoid contact with others.
“When the indicator is orange, you want to stay at home as often as possible,” said the mayor on Thursday. “And you should assume everyone around you is infectious.”