(ATTN: REWRITES headline, lead; UPDATES with more details throughout; CHANGES photo)
SEOUL, June 1 (Yonhap) -- Cluster infections at churches are again putting health authorities on edge Monday following a series of mass infections tied to clubs and a distribution center.
The country reported 35 additional cases of COVID-19, including 30 local infections, raising the total caseload to 11,503, according to the Korea Centers for Disease Control and Prevention (KCDC).
Monday's newly added cases marked a slight rise from 27 identified the previous day. But the tally appears to be on a downward trend after it hit a nearly two-month high of 75 on Thursday.
Of the 30 local infections, 24 cases were traced to churches in Gyeonggi Province that surrounds Seoul and Incheon, west of the capital.
A rise in sporadic infections put health authorities on higher alert over a potential wave of mass infections in the densely populated metropolitan areas -- Seoul and the surrounding areas.
Incheon alone reported 18 new cases, followed by 12 in Gyeonggi Province and one in Seoul.
The country is still grappling with cases traced to a logistics center run by e-commerce leader Coupang in Bucheon, just west of Seoul, and infections tied to Seoul's nightlife area of Itaewon.
The logistics center cluster has brought to the fore the vulnerability of workplaces where many people work in a close environment without strictly complying with quarantine measures.
At least 112 cases have been traced to the distribution facility since the first patient was confirmed in late May, health authorities said.
The total caseload liked to Itaewon clubs and bars reached 270 as of noon Sunday, according to the KCDC.
Alarmed by the spike in virus cases, health authorities have imposed a tighter social distancing campaign in the densely populated metropolitan area of Seoul and the surrounding region over the next two weeks through June 14.
After 45 days of stricter social distancing, the country switched to the scheme on May 6 to enable citizens to carry out social and economic activities under quarantine rules amid a slowdown in virus infections.
"Seoul's metropolitan areas need more stringent responses as new virus infections and cases whose transmission routes are not traceable have sprung up sporadically," Yoon Tae-ho, a senior health official, said in a briefing.
The country, meanwhile, added five imported cases and one additional death, raising the total death toll to 271. The fatality rate was 2.36 percent.
The total number of people released from quarantine after full recoveries stood at 10,422, up 17 from the previous day.
The country has carried out 921,391 tests since Jan. 3.
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One month into eased social distancing, S. Korea wrestles with cluster infections, cases with unknown routes