North Korea fired what appear to be ballistic missiles on Saturday, the Japanese Coast Guard said, citing the Defense Ministry.
At least two projectiles were fired from North Korea, the coast guard said.
According to state broadcaster NHK, referring to “multiple sources within the government”, the projectiles appear to have ended their course outside of Japan’s exclusive economic zone.
“What appears to be a ballistic missile was launched from North Korea,” the coast guard said in a statement released at 6:47 a.m. (2147 GMT).
In a second press release issued at 7:01 a.m., they announced that another ballistic missile had obviously been fired.
North Korea has conducted a record number of weapons tests this year, including ballistic missiles.
If confirmed, it would be the fourth such launch in a week.
Pyongyang fired two short-range ballistic missiles on Thursday, according to the South Korean military, hours after US Vice President Kamala Harris left South Korea.
During her visit, Ms. Harris traveled to the heavily militarized border with North Korea, as part of a trip to bolster defense commitments between Washington and Seoul.
The United States has some 28,500 soldiers in South Korea to help that country face the threat of an attack from its northern neighbor.
Seoul on Thursday announced its participation in anti-submarine maneuvers with Japan and the United States for the first time since 2017.
South Korean officials said this week they had indications that Pyongyang could be preparing a ballistic missile launch from a submarine.
South Korean and US officials have also been warning for months that North Korea is preparing to conduct another nuclear test.