South Korea's southern port city of Busan will raise its social distancing to the highest Level Four from Tuesday amid a surge in COVID-19 cases.

The city government said on Sunday that it will upgrade its social distancing by one notch to Level Four from 12 a.m. Tuesday.

Busan City will be under the toughest distancing measures until midnight on August 22.

The move comes just two days after the local municipality announced it will maintain the Level Three distancing until August 22 and keep its ban on entertainment facilities.

The port city reported a daily record 171 coronavirus cases on Sunday, with its accumulated caseload surpassing nine thousand.