Hong Kong is planning to enforce a lockdown to ensure a mandatory COVID-19 testing drive planned for this month is effective, Sing Tao Daily and other domestic media reported Tuesday, as the worst virus outbreak in the city so far continues to snowball.

Testing of the financial hub’s 7.4 million people will start after March 17, Sing Tao said, citing people it didn’t identify.

Officials are aiming to test the whole city three times over nine days, with a stay-at-home order in place to maximize impact, Sing Tao and other media including the South China Morning Post reported. Hong Kong’s core financial services including the operations of the stock exchange will continue during the testing period, according to the report. Officials were said to be still working out the details.