Ontario reported 978 new COVID-19 cases on Saturday, the most on a single day since the outbreak began in late January.
Saturday's count surpasses the previous high of 939, which was reported on Oct. 9.
Health Minister Christine Elliott said the majority of the new cases are concentrated in Toronto, which once again led the way with 348. Another 170 cases were reported in Peel Region, followed by 141 in York Region and 89 in Ottawa.
A handful of other areas saw double-digit increases as well:
Durham Region: 51.
Eastern Ontario: 43.
Simcoe Muskoka: 23.
Halton Region: 21.
Waterloo Region: 14.
Niagara Region: 10.
The number of patients hospitalized in Ontario due to COVID-19 now sits at 294, an increase of 18 since Friday.
There are 82 people in intensive care units, an increase of four, and 53 people are on ventilators, an increase of six.
The province's seven-day average of new daily cases has also broken a new record. As of Saturday, it sits at 803 — higher than any other day so far this year.
Ontario's cumulative total of cases now sits at 69,331. Some 625 cases were marked as resolved in Saturday's update.
Six more people have died of COVID-19 in Ontario. The provincial death toll now stands at 3,086.
WATCH | CBC's Natalie Nanowski breaks down Ontario's new numbers:
Nearly 44,200 tests completed
Meanwhile, Ontario's network of community, commercial and hospital labs processed 44,151 novel coronavirus test samples since its last daily report.
While that figure marks the highest number of daily tests completed so far this week, it still falls short of Ontario's goal of processing 50,000 tests per day by mid-October. The province also set a goal of processing 68,000 tests by mid-November.
Dr. Sumon Chakrabarti, an infectious diseases specialist at Trillium Health Partners in Mississauga, Ont., attributes that shortfall to Ontario's tightened testing criteria and move to appointment-only testing.
"This has caused a bit of problems because we're getting people to make appointments, but there are some double bookings happening, people not showing up," he told CBC News Network on Saturday.
"This has put a little bit of a wrench in plans."
But Chakrabarti said despite those issues, he hopes testing will ramp up in the coming weeks.
"It's important for us to have the right testing at the right time and not just the big numbers. Otherwise you start to get a picture that does not actually represent what's happening on the ground," he said.
Halton mayors ask to stay in Stage 3
Meanwhile, two mayors and MPPs from Halton Region wrote a letter to Dr. David Williams, Ontario's chief medical officer of health, on Friday, pleading with him to refrain from imposing Stage 2 restrictions on the area.
"Last week when York Region faced new restrictions, Halton Region came together. We acted quickly to implement several recommendations made by our Medical Officer of Health," the letter reads.
"These measures are working."
The letter — signed by MPPs Parm Gill and Jane McKenna, as well as Halton Regional Chair Gary Carr, Burlington Mayor Marianne Meed Ward and Milton Mayor Gordon Krantz — also noted that the region's positivity rate has not moved past public health's "high alert" range of 2.5 per cent.
"In these unprecedented times, individuals and businesses need to have some level of predictability and stability. This is why we are also calling on you to clearly define the criteria used to determine when further restrictions or rollbacks are required, as well as the criteria that must be met for lifting any restrictions or rollbacks," the letter reads.
The plea comes after Premier Doug Ford hinted on Friday that Halton could soon join the list of regions with stricter COVID-19 measures.
Ford said provincial officials will examine the situation there over the weekend to decide whether the area needs to be moved back into a modified Stage 2.
The restrictions mean restaurants can only offer outdoor service, and gyms and theatres must close.
"It's concerning right now, I've seen the numbers go up again," Ford said on Friday.
Asked if a similar move would be considered for Durham Region, where new cases are also increasing, Ford said the province will look at every area that's experiencing "a little escalation" and provide clarity on Monday.
Toronto, Peel Region and Ottawa moved to a modified Stage 2 — which includes the closure of gyms, movie theatres and casinos, and a ban on indoor dining in restaurants or bars — on Oct. 10, while York Region did so this week.
The tighter rules are set to be reviewed after 28 days, and Ford said he would make decisions on any steps beyond that based on the advice of the provincial health team.
Horwath calls for expansion of contact tracing
In a statement on Saturday, NDP Leader Andrea Horwath blamed Ontario's high case count on Ford's "refusal to invest in stopping the growth of the second wave."
Horwath said the province is sitting on more than $9 billion in pandemic support funding, more than $7 billion of which she said came from the federal government.
"Mr. Ford doesn't want to spend the money. And cases are skyrocketing as a result," she said in the statement
Horwath is calling for a "massive" expansion of testing and contact tracing in "every community" across the province.
She also wants to see enhanced protections in the long-term care sector, as well as a 15-student class cap in schools.
"People can't afford to have Mr. Ford delay another day," Horwath said.
10 patients, 4 staff infected at CAMH
The Centre for Addiction and Mental Health (CAMH) said on Saturday that 10 patients and four staff members so far have tested positive for COVID-19 due to an outbreak at its Queen Street site.
The news of the most recent confirmed cases comes after the hospital first reported an outbreak last weekend.
"We continue to remain vigilant about policies and procedures to keep staff and patients safe and we are working with our partners at Toronto Public Health on reporting, surveillance, and infection control," CAMH wrote in a statement on Saturday.
CAMH is not the only hospital that has reported outbreaks in Toronto over the last week. Sunnybrook Health Sciences Centre reported an outbreak in the facility's surgical unit on Friday and St. Joseph's Health Centre, along with Toronto Western Hospital, reported outbreaks last weekend.
Thermal blankets draw patio-goers
Some restaurants are looking for creative ways to keep dining available outside as COVID-19 hot spots in Ontario have reverted back to a modified stage two.
With indoor dining closed, restaurants in the Danforth neighbourhood in Toronto are part of a new initiative with the Broadview-Danforth BIA to entice customers to visit outdoor patios, despite chillier weather.
Beginning on Saturday, those who dine out on outdoor patios in the neighbourhood will receive a free thermal blanket and a $5 gift card to use at any BIA business in the area.
Some residents participated in the initiative on Saturday, wrapping themselves in the blankets to stay warm during the crisp, late October weather.