Shanghai reported three COVID-19 fatalities on Sunday, marking the first time deaths were registered in the city's latest outbreak which started at the beginning of March,  government officials announced on Monday.

The three cases — two people aged 91 and one aged 89 — suffered from serious preexisting medical conditions, including acute coronary syndrome, diabetes, hypertension, and sequelae of cerebral infarction, according to the government. None of them were vaccinated.

"Their condition continued to worsen after they were sent to the hospital and they died despite rescue efforts. The direct cause of their death was their underlying diseases," said Wu Qianyu, a primary inspector from the Shanghai Municipal Health Commission, at a press briefing.

According to the authorities, there were 16 severely ill COVID-19 cases in Shanghai as of Sunday.