WASHINGTON (AFP) -- Donald Trump vowed to temporarily ban immigration to the United States to combat the "invisible enemy" of coronavirus, claiming it would save American jobs as the world economy plunges into meltdown.

The announcement, a drastic new step in the US President's anti-immigration crusade, comes as the globe tries to chart its way out of an unprecedented health and economic crisis.

In just four months, the novel coronavirus has touched almost every nation on the planet, keeping billions of people at home and claiming more than 170,000 lives.

The US is the host of the world's deadliest outbreak, with more than 42,000 deaths and 784,000 known infections nationwide.

At least 22 million American jobs have also been lost as lockdowns suffocate commerce around the globe, resulting in the extraordinary spectacle of oil prices turning negative as demand evaporates.

After lending support to a spate of anti-lockdown protests in parts of the US, President Trump said late Monday he would halt immigration to the country -- a move likely to please his right-wing base in an election year.

"In light of the attack from the Invisible Enemy, as well as the need to protect the jobs of our GREAT American Citizens, I will be signing an Executive Order to temporarily suspend immigration into the United States!" he tweeted.

There were no further details about the measure or how long it would last.

Rival Democrats accused the Republican president of politicising the health crisis to push his anti-immigrant agenda and deflect blame for initially downplaying the dangers of the virus.

As death tolls in some of the hardest-hit countries stabilise, debates are raging over when and how to relax restrictions on business and ordinary life.

Many governments fear triggering another wave of infections but are also weary of the mounting economic costs and signs of social tension.

In a sign of what lies ahead, a gradual return of normalcy in Wuhan, the Chinese city where the virus first emerged, remains tinged with fear about fresh outbreaks of the disease.

The industrial city was released from quarantine two weeks ago, but many restaurants, for instance, have not reopened or are still only able to offer outdoor seating and takeout.

"We have very, very few customers," said Han, the 27-year-old owner of a soy drink stall.

"Everyone is worried about asymptomatic infected people," she said. "Business is just not as good as before."

In Europe, several countries are cautiously creeping out from confinement, buoyed by signs the worst of the virus may be behind them.

But large gatherings appear to be out of the question for the forseeable future.

While Germany is allowing smaller shops from florists to fashion stores to reopen, authorities cancelled Oktoberfest, a beloved beer-swilling festival in southern Bavaria, for the first time since World War II.

Spain also announced it was scrapping its annual bull-running festival in Pamplona, a centuries-old tradition that normally draws a over a million people.

In the UK, lawmakers encouraged to attend parliament via video link for the first time, following an extended Easter break.

Ghana became the first African country to lift coronavirus restrictions, sparking both relief and concern on the streets in Accra teeming with citizens after a three-week lockdown.

"It is a huge reprieve," hawker Jemima Adwoa Anim told AFP. "We had no money and at the same time couldn't step out to work to earn some cash."

Elsewhere, fear is building about how the most vulnerable will survive lockdowns that breed their own dangers.

In Latin America, weeks of confinement have seen a surge in calls to helplines for victims of domestic abuse.

Eighteen women have been killed by their partner or ex-partners during the first 20 days of Argentina's mandatory quarantine.

Appeals to helplines have also shot up nearly 40 percent.

"Every day, a women is abused, raped or beaten at home by her partner or her ex," said Ada Rico, from the NGO La Casa del Encuentro.

"In normal times, we would help her to file a complaint. These days, the urgency is to get her out of the house as quickly as possible.
The turmoil of the coronavirus fallout is playing out dramatically on the oil markets, where US crude prices bounced Tuesday but still fell below 0$ due to shrinking demand and a storage glut.

The price of a barrel of US benchmark West Texas Intermediate has turned negative because once its May contract expires Tuesday, buyers will need to take possession of the oil or move it to storage.

With demand sharply reduced due to the global economic freeze, there is little storage to be found, meaning traders preferred to effectively pay someone to take it off their hands.

"This isn't surprising, given flights are grounded and people are driving much less for work and leisure," said Tai Hui at JP Morgan Asset Management.

However, the oil market movements weighed heavily on US and Asian stocks, with Japan's Nikkei closing down nearly two percent and European equity markets opening in the red.

The virus has hammered the aviation sector particularly hard, with cash-strappedVirgin Australia announcing Tuesday it had entered voluntary administration -- the largest airline so far to collapse. (AFP)