The daily global death toll from COVID-19 topped 18,000 for the first time in the latest reminder of its deadly impact while countries further tightened restrictions on Wednesday in their struggle to get a grip on the new virus variants.

The United Kingdom on Wednesday announced a new rule under which citizens and permanent residents flying back from "high-risk" countries must quarantine in hotels.

Returning travelers must stay in hotels for 10 days while they complete the required self-isolation period, Home Secretary Priti Patel told lawmakers.

Non-UK arrivals from the targeted destinations - which include South America, Portugal, Cape Verde and South Africa - are already barred following the discovery of two virus variants detected in Brazil and South Africa.

The more infectious strain of the virus that first emerged in Britain has now spread to 70 countries, the World Health Organization said, while another detected in South Africa has been found in 31.

France also considered whether to order a third nationwide lockdown as the government admitted that current restrictions were not enough. "Maintaining the current regime looks very unlikely," spokesman Gabriel Attal said after a cabinet meeting, adding a nationwide nighttime curfew introduced on Jan 14 is "not sufficient at this stage".

France reported on Wednesday nearly 27,000 new cases over the latest 24-hour period, the biggest one-day jump in cases since Nov 18.

In Latin America, Colombia will ban flights from Brazil effective Friday over concerns of a variant of the coronavirus that is circulating in the country.

Colombian President Ivan Duque on Wednesday announced the 30-day measure. No flights will take off from Colombia to Brazil either.

The Colombian government on Tuesday decreed three days of national mourning after the death of defense minister Carlos Holmes Trujillo from the disease.

Economic losses

By Thursday, there were more than 100.9 million infections worldwide, with more than 2.17 million deaths, data from Johns Hopkins University showed.

While necessary, waves of lockdowns and closures have led to severe economic losses and anger in some countries, including riots in recent days in the Netherlands.

Dutch police said on Wednesday the fourth night of the Netherlands' coronavirus curfew passed more peacefully than the previous three nights marred by rioting. Nearly 500 people had been detained and thousands fined, Reuters news agency reported.

Most rioters were youths or young men, who reportedly used social media apps to organize, officials said. The worst disturbances were in Rotterdam where police said 10 officers were hurt, the BBC reported.

The Netherlands has had nearly 1 million confirmed COVID-19 cases, with more than 13,000 deaths.

Neighboring Belgium expressed fears on Wednesday that the unrest could spread, with calls for protests against the country's tough lockdown and its 9 pm curfew mounting on social media. The Dutch curfew, which began on Saturday, also begins at 9 pm.

"The violent demonstrations that degenerated in the Netherlands have apparently incited certain people to call, also in our country, for demonstrations against the health measures," Belgian Interior Minister Annelies Verlinden's office said.

Jonathan Powell in London, agencies and Xinhua contributed to this story.