The World Health Organization (WHO) announced Friday that it would classify the new B.1.1.529 COVID-19 strain as a “variant of concern,” and labeled it with the Greek letter “omicron.”

WHO made the announcement after an emergency meeting of its Technical Advisory Group on SARS-CoV-2 Virus Evolution. President Biden was briefed Friday on the new variant, the White House said.

“The B.1.1.529 variant was first reported to WHO from South Africa on [Nov. 24, 2021]. The epidemiological situation in South Africa has been characterized by three distinct peaks in reported cases, the latest of which was predominantly the delta variant,” the WHO explained. “In recent weeks, infections have increased steeply, coinciding with the detection of B.1.1.529 variant. The first known confirmed B.1.1.529 infection was from a specimen collected on [Nov. 9, 2021].”