South Korea has reported nine more cases of COVID-19 variants, which are known to be more contagious, raising the total so far to 27. 

The Korea Disease Control and Prevention Agency(KDCA) said Monday that analysis conducted since last week has confirmed nine additional cases of variants among recent imported infections.

This breaks down to four cases of the U.K. variant, three of the South Africa strain and two people infected with the Brazilian variant.

Seven were detected upon arrival while two later tested positive. One official noted that no cases have been found so far among people who came in contact with the confirmed patients.

The U.K. variant in particular is known to be one-point-seven times more contagious than the existing COVID-19 strain.

The Seoul government is tightening entry control to block the influx of variants from overseas including mandating all foreign arrivals to submit negative PCR tests.