The United States on Tuesday recorded 68,524 new coronavirus cases in the previous 24 hours, Johns Hopkins University reported in its real-time tally.

The country, which is the world's hardest-hit, has now registered a total of 3,891,893 infections, the Baltimore-based university said at 8:30 pm (0030 GMT Wednesday) 

Another 961 more deaths were recorded, bringing total fatalities to 141,883.

The United States has seen a resurgence of cases, particularly in the so-called Sun Belt, stretching across the south from Florida to California.

President Donald Trump, in a return to his presidential coronavirus briefings Tuesday, warned that the US coronavirus crisis is likely to "get worse before it gets better."

He also urged Americans to wear facemasks to help prevent the spread of the highly contagious virus.

Australia posts record new infections

Australia reported a record 501 new coronavirus infections Wednesday, nearly four months after the pandemic initially peaked in the country, with authorities warning of a critical new phase in its two biggest cities.

Most of the cases were reported in Victoria state, where authorities have struggled to bring an outbreak in Melbourne under control despite an almost two-week lockdown on Australia's second-biggest city. 

Australia's new coronavirus infections previously peaked on March 28 when 459 cases were reported, according to data compiled by AFP, before the country appeared to bring the virus under control and began easing harsh restrictions. 

Australia, like neighbouring New Zealand, has been lauded for its pandemic response.

Victoria Premier Daniel Andrews announced 484 new cases and two more deaths in the state Wednesday, bringing the state's total active cases to just over 3,400.

Australia has now recorded almost 13,000 cases of COVID-19 and 128 fatalities in a country of about 25 million.

Melbourne residents will be required to wear masks outside from midnight -- making the city the first place in Australia to mandate face coverings in public -- in a new effort to slow the virus spread.

But Andrews said "further behaviour change" would still be required, after analysis showed almost nine in 10 people diagnosed with coronavirus over the two weeks to Tuesday did not self-isolate between feeling sick and seeking a COVID-19 test.

Just over half of people also failed to stay at home between being tested and receiving their results, he added, saying authorities believed insecure work conditions were a key driver of the trend.

Andrews said casual workers across a range of industries, who do not get sick leave provisions, were worried about "feeding their kids, paying their bills" but could apply for a Aus$1,500 ($1,070) hardship payment if they contract the virus.

There are growing fears about the virus spreading through vulnerable populations after outbreaks at several nursing homes while inmates at six prisons have been confined to their cells after a guard tested positive.

The outbreak has left Australia rattled and dampened hopes of a speedy economic recovery.

- 'Most critical' -

An inquiry into how the virus spread in Melbourne heard this week that many cases were likely linked to infection control breaches at hotels used to quarantine residents returning from overseas.

Victoria has effectively been sealed off from the rest of the country in an effort to contain the virus, but new cases have been detected in neighbouring New South Wales state.

New South Wales Premier Gladys Berejiklian described the coming weeks as "the most critical" since the height of the last lockdown, when the state held the mantle of Australia's hardest-hit region.

Several clusters have emerged in Sydney, which health officials believe sprung up after an infected man from Melbourne visited a popular pub.

"We are not out of the woods by any stretch, quite the opposite," Berejiklian told a press conference. 

"We remain on high alert and we have some level of anxiety as to the extent of community transmission."

Mexico's death toll passes 40,000

Mexico on Tuesday passed 40,000 deaths from the novel coronavirus pandemic as the country, which has the fourth-highest COVID-19 death toll in the world, struggles to contain the disease.

A daily technical report recorded a total of 40,400 deaths from the virus, after adding 915 more fatalities in the last 24 hours. The first case in Mexico was detected on February 28.

This week President Manuel Lopez Obrador vowed to improve health standards in the nation to help its combat the virus threat. 

He pledged to protect those vulnerable to COVID-19, including tackling "diseases caused by hunger and poverty," launching "a permanent campaign" to promote healthier eating and lifestyles, and treating hypertension, diabetes and obesity as a priority.

"We want to remember those who died from the COVID-19 pandemic, and send a loving, fraternal hug to their relatives, to their friends," Lopez Obrador said in a video released on social media.

Mexico, with 127 million inhabitants, has the second-highest death toll in Latin America after Brazil, which has 80,000 deaths. 

Hundreds of virus-infected bodies recovered from Bolivian streets, homes

Bolivian police said on Tuesday they recovered more than 400 bodies from streets and homes over a five-day period, with 85 percent of the dead believed to have had coronavirus.

A total of 191 bodies were recovered in the Cochabamba metropolitan area alone from July 15-20, with another 141 collected in La Paz, national police director Coronel Ivan Rojas told journalists.

In the country's biggest city, Santa Cruz, authorities recovered 68 bodies.

The Santa Cruz metropolitan area is the worst affected by coronavirus in Bolivia and accounts for almost half of the country's more than 60,000 cases.

Some 85 percent of the bodies were "positive cases for COVID-19 and cases with COVID symptoms, so they will be recorded as suspected cases," said Rojas.

The rest died of "other causes, meaning death from an illness or a violent cause," he added.

According to the national epidemiological office, the western regions of Cochabamba and La Paz are experiencing a "very rapid increase" in coronavirus cases.

Andres Flores, director of the Forensic Investigations Institute, said that between April 1 and July 19 more than 3,000 bodies that were recovered outside of hospital settings had been identified as either confirmed or suspected coronavirus cases.

Bolivia has recorded more than 2,200 confirmed coronavirus deaths among its 11 million population.