The United Kingdom is expected to announce tight lockdown restrictions Monday, following a recommendation from the nation's chief medical officers to move to the highest COVID-19 alert level -- alert level 5 -- across the country. The U.K. has been at alert level 4 since September.

"Cases are rising almost everywhere, in much of the country driven by the new more transmissible variant," the chief medical officers said in a statement Monday. "We are not confident that the NHS can handle a further sustained rise in cases and without further action there is a material risk of the NHS in several areas being overwhelmed over the next 21 days."

British Prime Minister Boris Johnson is set to announce additional measure to control the virus during a televised address Monday evening.

-ABC News' Zoe Magee contributed to this report.

The entire 2021 NCAA men's championship basketball tournament will be held in Indiana, the NCAA announced Monday.

The NCAA is partnering with the local health department in Marion County to test players, coaching staff, administrators and officials for COVID-19. Teams will stay on dedicated hotel floors and meetings and dining halls with be socially distanced.

"The Marion County Health Department has approved medical protocols shared by the NCAA and will continue collaborating with the NCAA leading up to and during the championship," the NCAA said in a statement.

The majority of those contests will be held in Indianapolis.

The 2020 NCAA Tournament was canceled due to the COVID-19 pandemic.

ABC News' Joshua Hoyos and Matthew Stone contributed to this report.

A record-breaking 125,544 people in the United States are currently hospitalized with COVID-19, with six states -- Alabama, California, Georgia, North Carolina, South Carolina and Texas -- reporting record hospitalizations on Jan. 3.

While daily COVID-19 figures remain skewed because of a holiday-related backlog, data from December shows a grim trend, according to an ABC News analysis of data collected by The COVID Tracking Project, a volunteer-run effort to track the U.S. outbreak. December was the worst month so far for infections, hospitalizations and deaths. In less than eight weeks, the U.S. jumped from 10 million cases to 20 million cases on Jan. 1.

Over the course of December, the U.S. reported 77,082 deaths from the virus, bringing the national death toll to 351,590, according to data from Johns Hopkins University. The U.S., which leads the world in COVID-19 fatalities, accounts for nearly 20% of the world's total death toll.

In different terms, 1 in every 940 Americans has died of COVID-19.

ABC News' Arielle Mitropoulos contributed to this report.

Scotland will re-enter a nationwide lockdown at midnight in an effort to curb the spread of the novel coronavirus.

Scotland's First Minister Nicola Sturgeon announced the move Monday, telling Scottish Parliament that people across the mainland will be required to stay at home until at least the end of January. People must work from home where possible, group exercise will be banned, places of worship must shutter and schools will remain closed to most students.

The island areas will remain under Level 3 restrictions but will be closely monitored, Sturgeon said. All of Scotland has been under either Level 3 or 4 restrictions in recent weeks.

The situation will be reviewed on Jan. 18, Sturgeon said.

The new restrictions come as the country battles a rise in COVID-19 infections, with 15% of tests currently returning a positive result. Sturgeon told Scottish Parliament that she was "more concerned about the situation we face now than I have been at any time since March last year."

"It is essential that we further limit interaction between different households to stem the spread and bring the situation back under control, while we vaccinate more people," the first minister said. "In short, we must return for a period to a situation much closer to the lockdown of last March."

The United Kingdom saw another day of rising coronavirus cases, deaths and hospitalizations, according to the British government.

The nation recorded 54,940 new cases Sunday, bringing the total number of cases to 3,072,349, the health data showed. The seven-day average for new cases rose from 21,698 on Dec. 10 to 61,106 on Jan. 1, the British government said.

The U.K. saw 563 new COVID-19-related fatalities Sunday, according to the health data. The country has 81,431 total deaths since the start of the pandemic, the government said.

There are currently 32,294 people hospitalized in Britain. The seven-day average for new hospital admissions rose from 1,728 on Dec. 10 to 3,345 on Jan. 1, officials said.