The two COVID-19 deaths reported on the Chinese mainland on Friday had only mild COVID-19 symptoms and the primary cause of their deaths was severe underlying illnesses, a health official said on Saturday.

Jiao Yahui, director of the National Health Commission's Bureau of Medical Administration, said both patients were aged above 60 and had serious preexisting diseases. One of them was unvaccinated.

She said among the 29,000-plus COVID-19 patients in hospitals currently, 95 percent are asymptomatic or mild cases. The proportion of severe or critical cases only takes up less than 0.1 percent.

Jiao added that China has taken comprehensive measures to improve its treatment capability.

The two fatalities reported on Friday were the first on the Chinese mainland since January of last year. They happened in Jilin province in Northeast China, the region hardest hit by the novel coronavirus during this round of outbreak.