SHANGHAI, April 29 (Reuters) - As many as 12.38 million Shanghai residents, nearly half the population of the city, are now in lower-risk areas, meaning they can leave their homes, the government said on Friday (Apr 29).

Shanghai, battling China's largest ever COVID-19 outbreak, put the entire city into lockdown at the beginning of the month, though it has cautiously lifted some restrictions on residential areas that have gone two weeks without a positive case.

The city classifies each housing unit according to three levels of risk, designating those that have not seen a COVID-19 positive case for 14 days as "prevention zones", allowing residents to go out for "appropriate" activities.

By Thursday, the number of people living in high-risk "sealed and controlled zones" - subject to the strictest lockdown measures - was 5.27 million, down by 6.6 million since the last readjustment on Apr 20.

"The number of people in the sealed and controlled zones has clearly fallen," Zhao Dandan, deputy director of Shanghai's health commission, told a media briefing.

Another 5.93 million medium-risk residents are now allowed, in principle, to leave their apartments but are still confined to their compounds.

The government said 52 people died of COVID-19 on Apr 28, up from 47 a day earlier. Their average age was 84.

The city reported 9,545 new asymptomatic cases on Thursday, up from 9,330 a day earlier, with symptomatic cases also surging to 5,487, from 1,292 the previous day.

The coronavirus first emerged in the Chinese city of Wuhan in late 2019 and for the next two years authorities managed to keep outbreaks largely under control with lockdowns and travel bans.

But this year the fast-spreading Omicron variant has tested China's "zero-COVID" policy.