Given the poor medical system in the north and its chronically malnourished population, "a very large outbreak could be devastating," he said.
With United Nations sanctions stifling North Korea's economy in recent years, illegal smuggling across the border with China has become a lifeline. But fear of Covid-19 has slowed both smuggling and legal trafficking.
Covid-19 "has accelerated the impact of sanctions on North Korea," said General Abrams.
North Korea's trade with China fell this year, according to official figures. To make matters worse, the north was hit by three typhoons in quick succession, severely damaging homes, farmland, roads, bridges and mines.
In a series of emergency meetings by the ruling Labor Party over the past few weeks, Northern leader Kim Jong-un has admitted that his five-year plan to rebuild the economy has failed. But he has ordered the government to undertake restoration efforts without accepting outside help and instructed the military to direct the restoration work.
The coverage was written by Kenneth Chang, Choe Sang-Hun, Emily Cochrane, Abdi Latif Dahir, Michael Gold, Peter S. Goodman, Marie Fazio, Sophie Hardach, Sarah Kliff, David Leonhardt, Dan Levin, Patricia Mazzei and Richard C. Paddock . Saw Nang, Roni Caryn Rabin, Karan Deep Singh, Megan Specia, Jim Tankersley, Kate Taylor and Noah Weiland.