KITCHENER -- A stay-at-home order has come into effect in Waterloo Region and across Ontario.

The province has also declared a third state of emergency.

“The COVID-19 situation is at a critical stage and we must act quickly and decisively to stay ahead of these deadly new variants,” said Premier Doug Ford in a news release. “By imposing these strict new measures we will keep people safe while allowing our vaccination program to reach more people, starting with our high-risk population and identified hot spots. Although this is difficult, I urge everyone to follow these public health measures and together we will defeat this deadly virus.”

The order came into effect at 12:01 a.m. Thursday and stay in effect for four weeks.

"Unless it's for an essential reason, please stay home," Ford said at a press conference on Wednesday afternoon.

READ MORE: What is considered essential under Ontario's stay-at-home order?

Provincial officials say people should only leave their homes for essential purposes, like going to the grocery store or pharmacy, accessing health-care services, exercising outdoors and for work that can't be done remotely.

Under the order, all retail stores except for grocery stores and pharmacies will close to in-person shopping. Big box stores can only sell essential goods such as groceries, household cleaning supplies, pharmacy items, health-care items, personal care items and pet care supplies. Garden centres and nurseries can operate at 25 per cent capacity.

Local malls will only be allowed to offer curbside pickup, which must be done at designated sites and by appointment only.

Education Minister Stephen Lecce said schools won't close under the stay-at-home order, although Wellington-Dufferin-Guelph has closed classes for in-person learning until at least April 18 following a Section 22 order from local Medical Officer of Health Dr. Nicola Mercer.

Waterloo Region's Medical Officer of Health said people should prepare for the possibility of moving to online learning after April break. She said she's monitoring case counts closely.

Waterloo Region reported 63 more COVID-19 cases on Wednesday, bringing the total number of cases rose to 12,333, including 11,680 resolved ones and 243 deaths.

Shoppers were out in the region in droves on Wednesday evening in anticipation of the restriction changes.

"You see the lineup here, everwhere has got a lineup now, it's just ridiculous," said one shopper at The Boardwalk. "So as of midnight everything's shut down, but right now it's a free for all."

While some told CTV News they were just there for essential supplies for them and their family, another had a more specific task in mind.

"It's my son's fourth birthday in a couple weeks, so this will be the second birthday he has been locked down for, half of his life," he said. "I just wanted to get him a couple extra presents so we can celebrate."

With files from