The number of new deaths rose slightly to 143, bringing the total fatalities in mainland China to 1,523. The total number of confirmed cases in the country now stands at 66,492, according to a notice from China's National Health Commission.

COVID-19, a disease stemming from a new form of coronavirus, has spread to more than 24 countries since December, when the first infections appeared in central China.

Saturday marks the second day the number of new COVID-19 cases fell since a spike Thursday, when the hardest-hit province of Hubei began including clinical diagnoses in its official count. Using the wider scope of classification, the central Chinese province reported 15,152 cases, including 13,332 that were diagnosed using doctors' analyses and lung imaging, as opposed to the prior standard of laboratory testing.

Hubei health authorities said in the notice that the new method was adopted to facilitate earlier treatment for those suspected of infection.

"The current fight against the novel coronavirus epidemic is a major test of China's system and capacity for governance," Chinese President Xi Jinping said during a Communist Party Central Committee meeting Friday, according to state media.

"In response to the shortcomings and deficiencies exposed by the epidemic, (the government) should work to strengthen areas of weakness and close up loopholes," Xi said.

China has imposed unprecedented measures in a sweeping campaign to contain the virus. At the outbreak's epicenter in the central province of Hubei, cities with a combined population of more than 60 million have been placed under lockdown, with outbound transportation halted and virtually all public activities suspended.

People returning to Beijing will now have to isolate themselves either at home or in a concentrated area for medical observation, said a notice from the Chinese capital's prevention and control work group published by state media late Friday.

The notice warns there will be legal consequences for those who don't comply with the 14-day quarantine. It did not elaborate on how the isolation will be enforced. While Beijing returnees were previously ordered to "self-quarantine" for two weeks, that measure allowed for occasional outings and implementation varied across neighborhoods.

Chinese officials have warned that COVID-19 may spread further as migrants return to their jobs in cities or other provinces after a prolonged Lunar New Year holiday.