(Bloomberg) -- Singapore restricted travel from seven African countries as the new Covid-19 strain found in parts of the continent raises alarm.

People who have been in South Africa, Botswana, Eswatini, Lesotho, Mozambique, Namibia and Zimbabwe in the last 14 days will not be allowed to enter or transit through Singapore from 11:59 p.m. local time on Nov. 27, the Ministry of Health said in a statement Friday. The restriction will apply to those who had already obtained prior approval for entry into the city-state.

Returning Singapore citizens and permanent residents will be allowed to enter but will be subject to a 10-day quarantine period at a dedicated facility. 

“There have been recent reports of a potentially more contagious variant of the Covid-19 virus, the B.1.1.529, which may be circulating in Botswana, Eswatini, Lesotho, Mozambique, Namibia, South Africa and Zimbabwe,” the Ministry of Health said.

Read more: What We Know About the New Virus Variant That’s Rocking Markets

“Scientists around the world are still finding out more about the new variant of virus, such as whether it is more transmissible than the delta variant, whether it is more likely to lead to severe illnesses, and efficacy of existing vaccines against this new variant,” the statement continued.

The Ministry of Health added that Singapore currently has no cases of the variant. Two cases of the strain have been found in Hong Kong.

Before Friday’s announcement, long-term pass holders and short-term visitors with a history of travel to six of those countries were allowed to enter Singapore but were subject to a 10-day isolation period at a dedicated facility. Those coming from South Africa had to spend a seven-day quarantine at their place of residence.

Singapore said the new border restrictions will apply for four weeks, and then be reviewed and extended if necessary.

Singapore has been gradually reopening to travel after more than a year of closed borders and trying to wall out Covid. It’s started a number of vaccinated travel lanes to facilitate activity in and out of the city, which was a key travel transit hub for Asia pre-pandemic.

©2021 Bloomberg L.P.