Seoul, South Korea (CNN) North Korea fired two "unidentified projectiles" into the waters between South Korea and Japan on Thursday afternoon, the South Korean government said in a statement.

It is unclear what exactly was launched, but South Korea's Joint Chiefs of Staff said the military "is maintaining its readiness by monitoring relevant movements in preparation for further launches."

Japan's Coast Guard said in a statement "it appears that North Korea has launched a missile" and advised ships to avoid the area.

If confirmed as a missile test, it would be the first by Pyongyang in nearly a month and the 12th since May. The country said it tested a new type of submarine-launched ballistic missile on October 2 . Experts voiced concern over that event because it was the first missile test by North Korea in some time that didn't involve a shorter-range weapon.

The US and North Korea held working-level nuclear talks a few days later , but those concluded without an agreement. Both sides offered a very different picture of events -- Pyongyang accusing Washington of lacking flexibility, but the State Department said the US "brought creative ideas and had good discussion with its DPRK counterparts," using the formal acronym for North Korea.

Read More