Japan will ban the entry of all foreign visitors starting Tuesday, as omicron, the new variant of COVID-19, continues to spread around the world, Prime Minister Fumio Kishida announced Monday. 

The news comes after Japan announced over the weekend that anyone arriving from South Africa and eight other countries had to quarantine for 10 days at a government-designated facility.

Two cases of the new variant omicron have been confirmed in Ontario, Canada, government officials announced Sunday.

"Today, the province of Ontario has confirmed two cases of the Omicron variant of COVID-19 in Ottawa, both of which were reported in individuals with recent travel from Nigeria. Ottawa Public Health is conducting case and contact management and the patients are in isolation," Christine Elliott, deputy premier and minister of health, and Dr. Kieran Moore, chief medical officer of health, said in a statement.

South Africa's President Cyril Ramaphosa addressed his nation on Sunday following the detection of the omicron COVID variant and said the country's National Coronavirus Command Council met Saturday to consider the recent rise in infections and the possible impact of the omicron variant. They have decided not to impose further restrictions at this stage.

"We considered the fact that when we encountered previous waves of infection, vaccines were not widely available and far fewer people were vaccinated," Ramaphosa said.

Ramaphosa said they will closely monitor infection rates and hospitalization over the coming days and will review the situation in another week.

Only 23.66% of South Africa's population is fully vaccinated against COVID, according to the Africa CDC.

President Joe Biden, who is returning to the White House Sunday afternoon, will be briefed in person by his COVID-19 response team and Dr. Anthony Fauci for an update on the omicron variant.

This is Biden's third briefing on omicron since Friday.

"This afternoon, the president will have an in-person briefing with members of his COVID-19 response team and Chief Medical Advisor to the President Dr. Fauci to provide an update on the omicron variant and the administration’s response," a White House official told ABC News.

-ABC News' Justin Gomez

Hospitals with limited capacity in Massachusetts are being asked to, once again, begin reducing elective surgeries.

The Massachusetts Department of Public Health released the updated guidance to hospitals on Tuesday. The guidance explains that, "on a statewide basis, hospitals are currently operating at over 90% inpatient capacity," which it says "is compounded by 500 fewer acute care inpatient beds available as a result of unprecedented staffing shortages."

"The current strain on hospital capacity is due to longer than average hospital stays and significant workforce shortages, separate and apart from the challenges brought on by COVID," Massachusetts Secretary of Health and Human Services Marylou Sudders said in a statement Tuesday. "COVID hospitalizations in Massachusetts remain lower than almost every other state in the nation, but the challenges the healthcare system face remain, and this order will ensure hospitals can serve all residents, including those who require treatment for COVID-19."

Although COVID-19 hospitalizations in Massachusetts are still significantly lower than last January, when more than 2,000 patients were receiving care, approximately 740 patients are currently hospitalized across the state.

Given the current "high census level" and expected increase in hospitalization rates, as seen last year during the period following Thanksgiving and through January, the Massachusetts Department of Public Health said a "concerted effort to preserve inpatient capacity" was necessary.

The current strain on the Bay State's health care system has been further exacerbated by staffing shortages.

"We are now seeing significant strain on hospital capacity due largely to workforce shortages and an influx of non-COVID-19 patients who deferred care and now need complex medical care," Steve Walsh, president and CEO of the Massachusetts Health and Hospital Association, said in a statement Tuesday.

The reduction of non-essential, non-urgent scheduled procedures will not apply to ambulatory services, pediatric care or immunizations, pregnancy terminations and essential, urgent inpatient procedures that have a high risk or would lead to a significant worsening of the patient’s condition, if deferred.

-ABC News' Arielle Mitropoulos