"North Korea fired each missile from the vicinity of Wonsan, Gangwon Province, at about 4:50 a.m. and 4:58 a.m. into the East Sea," Xinhua quoted the official as saying.
"Their range was about 500 km," the official added.
According the official, North Korea fired the missiles without designating no-sail zones, which the South Korean military view as a clear provocation.
"The missiles landed in international waters north-east of the East Sea," the official said.
The launch came three days after North Korea fired three short-range projectiles into the East Sea.
It also marks North Korea's 11th firing of short-range missiles and the fourth ballistic missile launch this year.