"Our military is monitoring the situation in case of additional launches and maintaining a readiness posture," the joint chiefs said in a statement, according to Yonhap. A US official said the weapons were "short range," AFP reported.
Citing a Japanese government source, Kyodo reported that the projectiles were "short-range ballistic missiles."
The joint chiefs noted that one unidentified projectile was fired at 5:34 a.m. and the other at 5:57 a.m., flying "around 430 kilometers" before falling into the Sea of Japan.
Earlier this year, Pyongyang resumed missile tests following a moratorium of over a year, as negotiations with Washington over disarmament and denuclearization stalled amid refusals to lower sanctions against the socialist country. Still, North Korean leader Kim Jong Un has signaled a willingness to return to the negotiation table, even while sending the parallel message that he's unwilling to give up his country's only guarantee of safety without substantial movement from the US toward reconciliation and a mutual defusing of tensions on the peninsula.
The country's most recent test was on May 9: a pair of missiles timed precisely 9 minutes before and 9 minutes after a US test of a nuclear Minuteman III intercontinental ballistic missile (ICBM) to send a message to Washington.