Surprise lockdowns are back after almost four weeks, with Block Two of Lido Garden in Sham Tseng shut down tonight.

Three of today's Covid-19 cases live in the Lido Garden block.

Authorities cordoned off the 36-story building at 8pm to test all 105 households by 1am tomorrow, with a goal to unseal the area at 7am.

The trio, two of whom went grave sweeping in Tuen Mun and Tseung Kwan O on April 3 were among 13 cases reported today.

Three were local infections from the same family, one of whom was an unknown-source patient, after the city recorded no such cases from Saturday to Monday.

The last lockdown was on March 19 at a Lohas Park block in Tseung Kwan O, after the building saw one unknown source case that day.