Daily new COVID-19 cases in South Korea remained in the 600s amid growing concerns about an outbreak of the highly transmissible Delta variant.

The Korea Disease Control and Prevention Agency(KDCA) said on Friday that 634 new cases were detected throughout Thursday, raising the country's cumulative caseload to 153-thousand-789.

Of the new cases, 602 were local infections while 32 were from overseas.

Authorities remain alert as the highly infectious Delta variant of COVID-19 is rapidly spreading across the world, with 190 infections detected in South Korea. 

The greater metro area accounted for about 77 percent of local transmissions, including 264 in Seoul and 179 in Gyeonggi Province.  

One more person succumbed to the virus, with the death toll now standing at two-thousand-nine and the fatality rate at one-point-31 percent.