The Marshall Islands, one of the last few places in the world untouched by Covid-19, has recorded its first two positive cases of the virus.
The government of the remote Pacific archipelago said two workers at a US base had tested positive after arriving from Hawaii on Tuesday.
The pair flew in on a military flight and have been isolated from the wider community since arriving.
The Marshall Islands closed its borders in March to keep the virus out.
Authorities stressed the two were "strictly border cases" discovered while the 35-year-old woman and 46-year-old man were in quarantine" with no threat of community transmission.
Safety measures in place have ensured they have not had contact with the community, said officials.
Most island nations in the Pacific closed their borders in the early days of the pandemic, amid concerns their weak healthcare systems would not be able to cope with an outbreak.
In June, the Marshall Islands eased restrictions to allow in mostly US military base workers and only with a three-week quarantine at the base.
Kiribati, Micronesia, Nauru, Palau, Samoa, Tonga, Tuvalu and Vanuatu are all believed to be still free of the virus.
The two positive cases arrived on Tuesday at the US base on Kwajalein atoll on a flight from Honolulu. Both are asymptomatic.
The local government called on people to "remain vigilant" and continue with basic precautions but said there was no need for any lockdown measures.
"Businesses and government operations will continue as normal until further notice," a government statement said.
While officials stressed there was no need for panic buying, they asked citizens to "continue their preparedness" by stockpiling two to four weeks of food and medicine.
With a population of 55,000 people, the Marshall Islands consists of two chains of coral atolls together with more than 1,000 islets, just north of the Equator in the Pacific.
It is a self-governing nation, but the US controls its security and defence and provides millions of dollars in aid every year.
The US rents the Kwajalein atoll as a base and missile test range.