The Chinese city of Wuhan conducted within 10 days 6,574,093 nucleic acid tests to screen novel coronavirus infections.
The tests were carried out between May 14 and 23, the local health authorities said.
Wuhan Municipal Health Commission said the city performed 1,146,156 tests on Saturday alone, more than 15 times the figure on May 14, when Wuhan kicked off the citywide testing campaign.
The aim was to better understand the number of asymptomatic cases of the virus.
The largest single-day number was on May 22.
Then the city of about 10 million people performed 1,470,950 tests.
The decision to expand the tests to cover all those who have not been tested before was made as Wuhan continued to report asymptomatic infections.
This raised public concerns as Wuhan reopened its factories, businesses and schools.
Prior to the campaign, the city had completed over 3 million nucleic acid tests.
The commission said the tests are voluntary and free of cost.
Priority was given to residential compounds that had previously reported infections, as well as old and densely populated buildings.
Children under six are not advised to take the tests.
The tests have been met with great enthusiasm from the public, with mask-wearing residents forming long queues at improvised testing sites.
They also maintain their physical distancing on the queues, according to Xinhua.