All arrivals from the United States will get tested for the new coronavirus within three days of self-isolation starting this week, health authorities said Sunday.

According to the Korea Centers for Disease Control and Prevention (KCDC), confirmed cases coming in from the US have been increasing steadily, which calls for the strengthened quarantine step against COVID-19 beginning Monday.

The KCDC data showed that 343, or 37.6 percent, out of a total of 912 imported cases came from the US But in the past two weeks, the portion jumped to 49.7 percent, the data showed.

Since March 27, all entrants from the United States have been faced with strengthened quarantine measures as South Korea grapples with a surge in imported cases of the new coronavirus.

Passengers from the US who do not show symptoms of COVID-19, such as a fever, are required to self-isolate at home for two weeks. Those who show symptoms are required to take tests upon arrival.

The country also has been enforcing both a two-week quarantine period and virus tests for all long-term arrivals from Europe, regardless of symptoms.

The strengthened measure comes as the country reports an increasing number of imported COVID-19 cases despite a gradual decline in domestic cases.

The country's new virus cases stayed around 30 for the second straight day Sunday on the back of a strict social distancing drive.

The country reported 32 more cases of the novel coronavirus, bringing the nation's total infections to 10,512.

Of the newly confirmed cases, 24, or 75 percent, came from overseas. (Yonhap)