SEOUL, South Korea — South Korea has reported its biggest daily jump in COVID-19 cases in 70 days as the government began imposing fines for people who fail to wear masks in public.

The 191 cases added to the country’s caseload Friday represented the sixth consecutive day of over 100 and the highest daily increase since Sept. 4.

Most of the cases were from the densely populated Seoul metropolitan area, where officials have struggled to stem transmissions tied to various places, including hospitals, nursing homes, churches, schools, restaurants and offices.

The steady spread of the virus has alarmed government officials, who eased social distancing measures to the lowest level since October to soften the pandemic’s shock on the economy.

Prime Minister Chung Sye-kyun said the government could “seriously consider” tightening social distancing again.

South Korea has so far weathered its outbreak without major lockdowns, relying on an aggressive test-and-quarantine program and mask-wearing behaviors of the public.

From Friday, officials started to impose fines of up to 100,000 won ($90) for people who fail to properly wear masks in public transport and a wide range of venues, including hospitals, nursing homes, pharmacies, nightclubs, karaoke bars, religious and sports facilities and at gatherings of more than 500 people.