Authorities in the Northern Marianas are investigating after a 70-year-old died at a quarantine facility on the main island, Saipan.
The person was being held in isolation at the Kanoa Resort, and was under investigation for Covid-19, but had not yet been tested.
However, it's being reported that the person had contact with the two people who tested positive for the coronavirus on Sunday.
Authorities in the Northern Marianas are growing increasingly concerned about how the territory would be able to handle a sustained outbreak of Covid-19.
The governor, Ralph Torres, on Sunday confirmed the territory's first two cases of the coronavirus at a hastily-arranged news conference on the main island, Saipan.
RNZ Pacific's correspondent on Saipan, Mark Rabago, said few details about the people have been released, with the government citing privacy reasons.
What is known is that one is a 49-year-old woman and the other is a 42-year-old man. Both are being held in isolation at a resort which has been set aside as a quarantine facility.
The government said one of them had recently travelled from nearby Guam, which has confirmed community transmission with more than 50 cases and one death.
"When we heard about Guam a couple of weeks ago we came to the conclusion that it was just a matter of time before the CNMI gets its first cases," he said, using the common acronym for the territory.
"Bascially the CNMI is on partial shutdown, there are no government offices open, public schools and private schools are also closed," he said.
Mr Rabago said the Northern Marianas had been in lockdown for weeks, with a territory-wide curfew imposed from 7 pm - 6 am, and even boat ramps out of bounds.
He said there were fears about what the coronavirus could wreak if it were to gain traction in the Northern Marianas islands.
"It's really problematic here on the island, we don't have a lot of medical resources," Mr Rabago said. "The hospital only has 87 beds and we only have a few ventilators."
"So if this pandemic really hits us hard we don't know how to cope."
Last week, the US government announced funding to set up on-island testing and other Covid-19 prevention measures in the Northern Marianas and its other territories and freely-associated states.