Health authorities have shifted their focus onto infections in households as the number of new cases among family members continues to rise at an alarming rate.
A total of 1,891 new Covid-19 infections -- 1,884 local transmissions and seven imported cases -- and a record high of 21 deaths were recorded on Saturday, said Dr Taweesilp Visanuyothin, spokesman of the Centre for Covid-19 Situation Administration (CCSA).
"Our concern now is that the disease is no longer out there but instead has already come into households, especially ones in Bangkok," he said, citing a sharp drop in the number of new infections detected in active-case finding operations carried out in at-risk places other than local communities.
"These fluctuations in the number of new cases are not satisfactory, and point to the need to adopt more stringent control measures," he said.
Of a total of 28,745 infected patients being treated, 829 were in critical condition and 270 of them were put on ventilators, he said.
The number of Covid-19 patients in critical condition rose by 12 and the number of these severely ill patients needing to be put on ventilators by 20 when compared to the numbers recorded on Friday, he said.
Of the 21 deaths logged on Saturday, nine males and 12 females, 10 were all in Bangkok, while two each in Chon Buri and Samut Prakan and one apiece in Ubon Ratchathani, Kalasin, Nakhon Si Thammarat, Chiang Mai, Chiang Rai, Pathum Thani and Phetchaburi, he said.
The cumulative number of Covid-19 infections has risen to 67,044, with 224 deaths, he said.
The vast majority of deaths, with a median age of 73, contracted the virus from their families, said Dr Taweeslip.
Bangkok, Chiang Mai, Chon Buri, Samut Prakan and Nonthaburi are the five provinces with the highest number of new infections.
At a meeting of the CCSA on Saturday, the Department of Disease Control set a goal of bringing daily new cases in the capital to under 400, or eight cases in each district, as the city steps up measures to control the spread.
City Hall now plans to kick off a new round of active case-finding by testing 1,800 people in target districts tomorrow, followed by 400 on Tuesday, 2,000 on Wednesday, 1,600 on Thursday and another 1,400 on Friday.
Because new cases reported in Bangkok and the surrounding provinces accounted for up to 44.2 % of all new infections last month, Prime Minister Prayut Chan-o-cha wants to focus on these areas as much as possible, said Rachada Dhanadirek, a deputy government spokeswoman.
More than 30,000 tests were carried out on April 5-30 during active case-finding operations by City Hall in Bangkok alone, while the Labour Ministry had conducted more than 45,000 such tests on workers registered under the social security system in Bangkok, Pathum Thani, Chon Buri, Chang Mai and Nonthaburi between April 17 and April 30, she said.