MONTREAL -- Quebec Premier François Legault announced Wednesday that four regions, after having their COVID-19 restrictions eased recently, will have that move reversed, while three cities will have what amounts to a shelter-in-place order.

"It's like we have to put populations in intensive care right now -- otherwise we're going to lose them," Legault said in a press conference to announce the changes. 

The Outaouais, Quebec City, Chaudière-Appalaches and Bas-St-Laurent regions will all move from orange to red zones under the province's alert system as of Thursday at 8 p.m., Legault said.

The three cities -- Quebec City, Lévis, and Gatineau -- are showing such alarming signs that the province is putting them on a 10-day lockdown, with schools and all non-essential businesses closed. Children will go to full-time remote learning.

That lockdown will also start Thursday at 8 p.m. and will last until April 12.

"Generally speaking, what we're saying is that the situation is critical, it is deteriorating, in those three cities," Legault said.

"People essentially have to remain at home, except if they absolutely have to go work."

The curfew in those three cities will also go back to 8 p.m. after being set at 9:30 across all orange and red zones.

Theatres, gyms and many other businesses will close, and the sale of non-essential products will be banned. Restaurants will be allowed takeout and delivery only. Houses of worship will have a capacity of 25 people.

It's more or less the same system that was in place in January, Legault explained.

Three of those regions only went to a more relaxed orange level on March 8, while the Outaouais has been orange since mid-February.

OTTAWA RESIDENTS WARNED NOT TO VISIT GATINEAU

Quebec Public Health Director Dr. Horacio Arruda also warned Ottawa residents against crossing the river to visit Gatineau, saying it's dangerous and should only be done for pressing reasons.

If you must go, be vigilant about wearing a mask, he said.

"It's highly, highly, highly recommended not to go to those zones, because there's public transmission," said Arruda.

Health Minister Christian Dubé also repeated what Legault said Tuesday -- that the province is in touch with the mayor of Gatineau and the Ontario government about trying to harmonize regulations across Ottawa and Gatineau.

"We will find a way to ensure there's less [interchange]" between the two regions," Dubé said.

The province is taking the action now in order to try to head off a dire future in a couple of weeks when the current trend in COVID-19 cases will hit hospitals, Legault said.

On Tuesday, a fifth region was named as very worrying, the Saguenay-Lac-St-Jean, but Legault said it's now considered to be in better shape.

MONTREAL STABLE FOR NOW, BUT THINGS CHANGING FAST

Montreal won't have its current rules changed for the time being, Legault said, as it's relatively stable.

However, overall, the situation is changing quickly as the province grapples with the spread of variants, and Montreal could end up having to backtrack to tighter restrictions as well, he later said.

He made the comment while defending himself against an accusation that the province has been "yo-yo-ing" back and forth between restrictions, which Legault had said he wanted to avoid.

"We're no different from anywhere else," he said, pointing to how French president Emmanuel Macron also recently changed restrictions.

"Everybody is in a situation where we're adjusting ourselves," he said. "If we hadn't wanted to take any risk, we would have closed more in Montreal, and we would have made a mistake, because... we've been able to give a bit of breathing room" to Montrealers, he said.

"But are we going to have to act next week in the greater Montreal area? Perhaps."

Arruda said he's watching the upcoming holiday weekend carefully to see if it changes Montreal's trajectory.

LISTEN:  When it comes to COVID and restrictions, what's next? Quebec Health Minister Christian Dube speaks to Andrew Carter on CJAD 800 radio