South Korea has decided to extend its ban on flights coming from the United Kingdom by one more week to January 7 aiming to prevent the spread of a new COVID-19 variant in the country.

All arrivals, including transfers, from Britain and South Africa must also submit negative test results while new visa issuance will be suspended, excluding diplomatic and official business and humanitarian reasons.

Also, additional tests will be conducted on all foreign arrivals before the end of their self-quarantine period.

The Korea Disease Control and Prevention Agency(KDCA) laid out the new measures in a Monday briefing on tightening entry control. The U.K. flight ban could be further extended depending on the situation next month.

KDCA chief Jeong Eun-kyeong said the new virus strain has been discovered in other parts of the world as well. South Korea confirmed its first cases of the more transmissible strain in a family of three that flew in from Britain last week.