The number of variant cases is on the rise in South Korea.
In the past week alone, 97 more cases of the variant strain have been identified, totaling up to 632 cases.
The southeastern port city of Ulsan has been hit the hardest.
"The Ulsan area has a high detection rate of virus variants. Statistics over the past six weeks show that the variants account for a little over 60 percent."
51 out of the 80 patients sampled were identified to have the UK strain of the virus, which is known to be 1.7 times more infectious than the original.
While many are worried about the variants speading to other areas of the nation, health authorities grapple with finding out why Ulsan in particular shows such a high percentage.
"It seems as if Ulsan has a high proportion of variants due to hidden cases and uncovered infection routes ."
Of the total infected patients nationwide, close to 15 percent were mutant strains.
Most were the UK, South Africa, and Brazil strains.
This comes as South Korea on Tuesday logged 541 total new infections, and 514 local infections.
The capital area saw the majority of the cases, with 182 local transmissions in Seoul and 117 in the surrounding Gyeonggi-do Province.
Outside the capital area, the coastal city of Gangneung in Gangwon-do Province has decided to raise its social distancing measures to level two after 43 foreign workers in the area tested positive.
Meanwhile, with a number of holidays coming up in May, health authorities warn against family outings due to the risk of infection.
As the country races toward its goal of herd immunity by November, health authorities say that the vaccination efforts center on not completely eradicating the virus, but on putting the country on track to some sort of normalcy.
Kim Yeon-seung, Arirang News