One more American service member and two US defense department employees tested positive for the new coronavirus upon arrival in South Korea this week, the US Forces Korea said Thursday.

The service member arrived at Osan Air Base in Pyeongtaek, some 70 kilometers south of Seoul, on a US government-chartered flight from the United States on Monday. The two workers for the Department of Defense Education Activity arrived at Incheon International Airport, west of Seoul, on a commercial flight Tuesday, according to the USFK.

All of them tested positive in their first mandatory COVID-19 test prior to entering quarantine, and they have since been transferred to an isolation facility designated for coronavirus patients at Camp Humphreys in Pyeongtaek, it added.

All USFK-affiliated individuals arriving in South Korea are required to undergo a virus test and are quarantined for 14 days.

Medical personnel administer a second test prior to their release.

"Thorough cleaning of all transportation assets and quarantine rooms has been completed," USFK said in a statement. "None of the new arrivals have interacted with anyone residing within USFK installations or the local community."

The latest virus cases brought the total number of USFK-related infections to 126. Of them, 90 were reported in July, and all of them were newly arriving service members, dependents and others.

USFK has not recorded an internal positive COVID-19 case since mid-April.

South Korea has seen a constant inflow of new coronavirus cases from abroad. On Thursday, the country added 18 new cases, including 11 imported cases, bringing the total caseload to 14,269, according to the Korea Centers for Disease Control and Prevention (KCDC). (Yonhap)