BEIJING  -- The close-off management of residential communities helped to keep social distancing and block the transmission chain and became the first line of defense in the battle against the COVID-19 outbreak, a health official said in Beijing on April 21.

Wu Hao, head of the Fangzhuang community health service center in Beijing, made the remarks at a press conference held by the National Health Commission.

"Based on the suggestions from experts, the city of Wuhan in Hubei Province started the close-off management of residential communities on February 11," said Wu, adding that many members of the Communist Party of China volunteered in communities to fulfill the shortage of hands in the front line.

Wu said experts sent by the commission provided onsite and video training and made various suggestions to the local staff to improve the epidemic prevention and control capability in Wuhan.

According to the commission, the number of severe cases dropped below 20 in Hubei for the first time, and no new confirmed cases were reported in Hubei on April 20.