Coronavirus infections in the United States have topped 11 million as outbreaks further intensified.
The US had hit 10 million Covid-19 cases just over a week ago. Deaths nationwide remain fewer than at the peak in spring, but they are also rising rapidly.
Forty states have reported record increases in Covid-19 cases this month, while 20 saw a record rise in deaths and 26 reported record hospitalisations.
The latest seven-day average shows the US is reporting more than 144,000 daily cases and 1,120 daily deaths, the highest for any country in the world.
Michigan and Washington states on Sunday imposed sweeping new restrictions on gatherings to slow the spread of the virus.
Michigan Governor Gretchen Whitmer ordered a ban on in-person high school and college classes as well as indoor dining service for three weeks starting tomorrow.
She banned public events at concert halls, casinos, theatres, skating rinks and other venues, while in-home gatherings will be limited to 10 people from no more than two households.
Ms Whitmer, a Democrat, warned that without aggressive action, Michigan could soon suffer 1,000 Covid-19 deaths a week.
"We're in the worst moment of this pandemic to date," she said. "The situation has never been more dire. We're at the precipice and we need to take some action."
White House coronavirus adviser Scott Atlas reacted to the Michigan orders by going on Twitter to urge state residents to "rise up" against them. After this drew criticism, Mr Atlas said he "NEVER was talking at all about violence".
Washington state Governor Jay Inslee, a Democrat, ordered a one-month ban on indoor services at restaurants and gyms, and a reduction of in-store retail capacity to 25 per cent.
Indoor gatherings will be banned outside of one's household and outdoor gatherings will be limited to five people.
US President-elect Joe Biden's top advisers on Sunday called for urgent action to address the situation, warning that Republican President Donald Trump's refusal to start a transition of power could further jeopardise the battle against the rampaging virus.
Mr Biden's advisers also said it would inhibit vaccine distribution planning and could affect additional government financial aid before Mr Biden, a Democrat, takes office in January.
"We're in a very dangerous period," Dr Michael Osterholm, a member of Mr Biden's Covid-19 advisory board and director of the University of Minnesota's Centre for Infectious Disease Research and Policy, said on NBC News' Meet the Press programme.
Calling the situation the most dangerous public health crisis since the 1918 influenza pandemic, he warned that unless action is taken now, "we're going to see these numbers grow substantially... Our future's in our hands".
"My worst fear is we will see what we saw happening in other countries, where people were dying on the streets," Dr Osterholm said. "The healthcare system is breaking, literally breaking."
Basic public health measures such as face masks have been politicised under Mr Trump, who has eschewed mask mandates even after contracting Covid-19 the previous month, while Mr Biden has backed their widespread use.
Still, some Republican governors have in recent days been forced to take action, with North Dakota joining 35 other states over the weekend in mandating masks and Iowa this week requiring them in certain circumstances.
Mr Ron Klain, Mr Biden's incoming White House chief of staff, on Sunday urged Congress to immediately pass Covid-19 relief legislation with new restrictions certain to take a toll.
"This could be a first example of bipartisan action post-election," Mr Klain told NBC News, adding that Mr Biden had spoken to congressional Democratic leaders, but not to Senate Republican leader Mitch McConnell, who has refused to publicly acknowledge Mr Biden as the President-elect.
Mr Klain said there had been no formal contact between Mr Biden's advisory panel and the White House coronavirus task force, which requires transition authorisation from the General Services Administration.
"It's really important in the smooth handing over of the information," top US infectious disease expert and White House task force member Dr Anthony Fauci said on CNN's State of the Union programme.
"It's nearly like passing a baton in a race, you don't want to stop and give it to somebody, you just want to essentially keep going."
Mr Biden's team plans meetings this week with Pfizer, which the previous week released positive initial data on its experimental Covid-19 vaccine, and other drugmakers, Mr Klain said.
Separately, previous US surgeon-general Vivek Murthy, head of Mr Biden's Covid team, has told Fox News that the country's coronavirus surge was "deeply alarming" but that a national lockdown was "a measure of last resort".
"The better way to think about these safety restrictions is more a dial that we turn up and down depending on severity" in a given area, Dr Murthy said.
REUTERS, NYTIMES