South Africa said on Friday that imposing restrictions on travellers from the country because of a newly identified COVID-19 variant was unjustified, after a British ban on flights from Southern African countries that others have followed.

“The UK simply went ahead and imposed the restrictions, without even engaging us, so that was basically a unilateral action,” said Health Minister Joe Phaahla.

Phaahla told a media briefing that South Africa was acting with transparency and travel bans were against the norms and standards of the World Health Organisation (WHO), which held an emergency meeting over the variant named omicron.

Scientists have so far only detected the variant in relatively small numbers, mainly in South Africa but also in Botswana, Hong Kong and Israel.

But they are concerned by its high number of mutations which raised concerns that it could be more vaccine-resistant and transmissible.

The WHO designated omicron as “of concern,” its most serious level, following a meeting of its technical advisory group.

British Prime Minister Boris Johnson and South African President Cyril Ramaphosa spoke on Friday afternoon and discussed ways to reopen international travel, a Downing Street spokesperson said.

In South Africa about 35% of adults are fully vaccinated, higher than in most other African nations, but half the government’s year-end target.

While the continent struggled initially to obtain sufficient doses, some countries including South Africa now have too much stock, with vaccine hesitancy and apathy slowing the inoculation campaign.

South Africa has been the country worst affected in Africa in terms of total reported COVID-19 cases and deaths, with nearly 3 million infections and more than 89 000 deaths since the start of the pandemic.

It had been experiencing a lull after a severe third wave of infections, until last week when new infections started to pick up.

On Thursday, it reported 2 465 new cases, almost double the previous day’s number. On Friday, there was a more modest rise in daily infections to 2 828 new cases.