South Korea's health authorities on Thursday confirmed three more cases of a more contagious variant of the new coronavirus that was first identified in Britain, bringing the variant's total caseload to 15.

The Korea Disease Control and Prevention Agency (KDCA) said the three people, all family members of a COVID-19 patient who was infected with the variant, were confirmed to have the new COVID-19 strain. The patient arrived in South Korea from Britain on Dec. 19 last year.

The KDCA said it is also conducting further tests on another family member to confirm whether they have been infected with the COVID-19 variant.

The World Health Organization (WHO) said the new variant, referred to as VOC202012/01, was identified through viral genome sequencing.

Initial analysis indicates that the variant may spread more readily between people than the original virus, with it maybe up to 70 percent more transmissible than the old variant.

On Wednesday, South Korea extended the ban on passenger flights departing from Britain, which has been in place since Dec. 23, for another two weeks to block the new virus variant.

The KDCA also said it will conduct further tests, known as next-generation sequencing, on arrivals from Britain and South Africa. The method provides an effective way to identify coronavirus strains and other pathogens without prior knowledge of the organisms.

Also, all foreign entrants must present papers showing negative PCR tests taken within 72 hours of their departure to the nation.

The country added 870 more COVID-19 cases on Thursday, staying below 1,000 for the third consecutive day, according to the KDCA. (Yonhap)