TORONTO -- More regions of Ontario will move into the third stage of the province's COVID-19 recovery plan later his week, the premier announced Monday as municipal leaders signalled they would support more stringent rules for some of the businesses cleared to reopen their doors.

Premier Doug Ford said Durham, Halton, Hamilton, Niagara, Haldimand-Norfolk, Sarnia-Lambton and York region will progress to the next stage on Friday, leaving only Toronto, Peel Region and Windsor-Essex to remain in Stage 2 due to higher COVID-19 case counts. The Stage 3 rules clear the way for restaurants to resume indoor service, as well as for businesses such as gyms, bars and theatres to begin welcoming customers.

"We won't rest until all of Ontario gets to Stage 3," Ford said at a news conference. "We won't stop until every worker in Ontario gets back to work and back on their feet."

Last Friday, 24 of the province's 34 public health regions advanced to the next stage of economic reopening and ushered in a host of loosened restrictions on public activities.

Regions in Stage 3 can hold indoor gatherings of up to 50 people, while outdoor gatherings can include as many as 100 as long as physical distancing measures are in place.

Restaurants are permitted to resume indoor service as long as tables are spaced two-metres apart to encourage physical distancing.

Ford did not say Monday when the remaining regions would move to Stage 3, but the province has said it needs four weeks of data to determine if case counts have lowered enough to permit moving forward safely.

Toronto, Peel and most of Windsor-Essex are just days away from completing that four-week term, while the towns of Leamington and Kingsville are still weeks from that point.

Meanwhile, the mayors of some of the Greater Toronto and Hamilton area's largest municipalities released a joint statement Monday asking the province to consider adopting additional public health measures for bars, restaurants and fitness facilities.

"We will support common sense measures taken by the Government of Ontario to do everything possible to protect the health and safety of GTHA residents and employees of reopening businesses and reduce the risk of these businesses having to close again," the statement said.

The mayors did not offer details on the sorts of measures they'd like to see in place.

Over the weekend, Toronto Mayor John Tory asked Ford to make masks mandatory inside restaurants and bars in that city when it eventually moves to Stage 3.

Tory said Monday that all it could take to see a spike in cases is one bar not following the rules.

"You could have these instances we've seen about superspreaders where people have suddenly infected 500 people directly and indirectly, and those people infect 500 more," he said.

Ford said his COVID-19 command table is discussing bar rules, but said municipalities have the power to impose their own restrictions on businesses.

Health Minister Christine Elliott urged people — especially young people — not to give into "COVID fatigue" and continue to abide by physical distancing, stick to one social "bubble" and wear a face mask.

"As we're opening up the economy it's more important than ever before to please follow the public health rules," she said.

Ontario's associate medical officer of health, Dr. Barbara Yaffe, said a spike in cases in Ottawa in recent days has been directly attributed to young people attending parties and ignoring public health rules.

"It's easy for people to forget that we're still in a pandemic," she said. "You will see the effect of that. The disease is still around, it will transmit. It may not be those young people who are severely affected, but it could be people around them."

Meanwhile, a hospital in Leamington, Ont. has increased its visitor restrictions after seeing a spike in COVID-19 cases in its assessment centre and emergency department over the past week.

Erie Shores HealthCare said in a statement that it has scaled back visitor access out of a "desire to keep our staff and patients as safe as possible during this uncertain time."

Ontario's chief medical officer of health said Monday the increase is outside of a surge in cases amongst migrant workers in the area, which also flared up again over the weekend with more than 60 new infections reported.

Dr. David Williams said provincial health officials are discussing how they can support the local health unit and hospital.

"We have put in place some steps to start to rectify, and to resource up, to make sure if it continues to accrue that we have enough people on the ground to respond in all fronts," he said.

Local leaders in Windsor-Essex formally requested the provincial government take charge of the pandemic response on local farms two weeks ago but have yet to hear back.

Ontario reported 135 new cases of COVID-19 and one new death from the virus on Monday.

The total number of cases now stands at 37,739, which includes 2,752 deaths and 33,513 resolved cases.

—With files from Jake Kivanc