North Korea previously fired a ballistic missile that landed in the Sea of Japan on May 4 (AP)

Japan's Coast Guard announced on Friday that North Korea has fired what is believed to be a ballistic missile.

"According to the information of the defense ministry, North Korea has carried out the launch of, presumably, a ballistic missile. Vessels are asked to monitor up-to-date information and, if fragments are detected, not to approach them and notify the coast guard," Sputnik reported.

Japanese media reported from government sources that the missile has dropped beyond Japan's exclusive economic zone.

The DPRK did not officially announce the launch and did not comment on what kind of projectile it was. South Korea's military said this was a ballistic missile that flew 470 km, with a maximum altitude of 780 km, reaching a speed of Mach 11.

If this projectile is indeed a ballistic missile, then this would be the 15th missile test conducted by Pyongyang this year, with the last being on May 4.

The DPRK has recently increased weapons testing to increase its deterrence capabilities. "Only when one is equipped with the formidable striking capabilities, overwhelming military power that cannot be stopped by anyone, one can prevent a war, guarantee the security of the country and contain and put under control all threats and blackmails by the imperialists," Kim said in late March.