LONDON -- A further 86 cases of the Omicron COVID variant have been reported in Britain, taking the total to 246, British health authorities confirmed Sunday.

This compares with a total of 160 on Saturday, an increase of more than 50 percent, according to the UK Health Security Agency (UKHSA).

Britain registered 43,992 new COVID-19 infections, bringing the total number of coronavirus cases in the country to 10,464,389, according to official figures released on Sunday.

The country also reported a further 54 coronavirus-related deaths. The total number of coronavirus-related deaths in Britain now stands at 145,605. These figures only include the deaths of people who died within 28 days of their first positive test.

The latest data came as British Health Secretary Sajid Javid said all international arrivals to Britain, including children over the age of 12, will need to take a pre-departure test from 0400 GMT on Tuesday. He added that they must be taken a maximum of 48 hours before departure.

In addition, from 0400 GMT on Monday Dec. 6, Nigeria will be on the red travel list. It joins several southern African nations which were put on it after the Omicron variant was first detected late last month.

"I think it's too late to make a material difference to the course of the Omicron wave if we're going to have one," professor Mark Woolhouse, a member of the Scientific Pandemic Influenza Group on Modelling (Spi-M), told the BBC, when asked about the new travel rules.

More than 88 percent of people aged 12 and over in Britain have had their first dose of vaccine and nearly 81 percent have received both doses, according to the latest figures. More than 35 percent have received booster jabs, or the third dose of a coronavirus vaccine.

To bring life back to normal, countries such as Britain, China, Germany, Russia and the United States have been racing against time to roll out coronavirus vaccines.