North Korean skaters Ryom Tae-Ok and Kim Ju-Sik grabbed one of the last qualifying spots for the Pyeongchang Olympics in September, becoming the first athletes from their country to secure a spot for the 2018 Games, starting in February.
But the ISU said North Korea had not confirmed its place by the Nov. 30 deadline, meaning that the slot would be passed to Japan, and making the pair's participation a matter for the IOC.
"In the hypothetical situation that PRK (North Korea) would subsequently ask for its quota confirmation, the ISU would refer such request to the IOC," the ISU told Reuters.
The IOC reserves the right to hand out special participation spots for the Games, and is eager to have North Korean athletes present. It has been helping several of them with equipment, travel and accommodation in their efforts to qualify.
South Korea has also said it will wait until the last moment for a North Korean team at the Games.
Tension on the Korean peninsula has risen in recent months as North Korean leader Kim Jong Un and U.S. President Donald Trump have exchanged threats and insults over the North's nuclear and missile development programme.
(Reporting by Elaine Lies in Tokyo, Writing by Karolos Grohmann)
