The Japanese coast guard has claimed North Korea may have fired a ballistic missile on Thursday.
"It may have been a ballistic missile," a defence ministry spokesman said. "It has not fallen within Japanese territory and is not believed to have come down within Japan's exclusive economic zone."
The coast guard has warned ships against coming close to any fallen objects and instead is asking them to provide related information to the coast guard.
Japan's Prime Minister's office for disasters and crisis management has tweeted that they are aware of the reports.
"We will inform you as soon as a follow-up report is available."
South Korea's joint chiefs of staff said they also believe North Korea has fired an unidentified projectile off the country's east coast into the sea.
North Korea's ballistic missiles are banned under United Nations Security Council Resolutions, and if the launch is confirmed, it would represent the first ballistic-missile test launch under new US President Joe Biden.
This comes after North Korea fired two short-range missiles at the weekend, US officials said on Tuesday.
Two senior Biden administration officials told reporters the activity involved weapons systems at the low end of the spectrum that was not covered by UN Security Council testing bans.