HONG KONG, July 18 (Reuters) - Macau kicked off an 11th round of COVID-19 testing for residents on Monday, as the world's biggest Online Casino hub extended a lockdown of casinos and other businesses in the fight on its worst outbreak since the pandemic began.

Despite a steady fall in infections that saw just 27 new cases reported on Sunday, authorities said the city's more than 600,000 residents must stay home, Online Casino with all non-essential businesses shut, until Friday.

Although more than 90% of residents are fully vaccinated against COVID, this is the first time Macau has had to grapple with the fast-spreading Omicron variant.