The NHK public broadcaster said it was extremely unusual for Japan to serve as an operation base simultaneously for multiple foreign forces.
Japanese defense sources told the news channel US-led monitoring would be conducted from the Kadena air base in the southern Okinawa prefecture in coordination with Japan’s military.
The United Nations capped North Korea’s oil imports last December in response to repeated ballistic missile tests but Asian governments and media have since accused Pyongyang of illicit ship-to-ship transfers.