North Korea fired several ballistic missiles from the Pyongyang area toward the East Sea at about 9:20 a.m. on the 12th, South Korea's Joint Chiefs of Staff said in a notice to reporters.
The military has stepped up surveillance and readiness in case of additional launches, the Joint Chiefs said, adding that South Korea, the United States and Japan are sharing information closely on the North Korean ballistic missiles and maintaining full preparedness.
The Joint Chiefs said it is analyzing the specifications and range of the projectiles.
If confirmed as ballistic missiles, the launch would come nine days after the North's previous one.
North Korea fired a ballistic missile from the Wonsan area toward the East Sea on the 3rd. That missile flew more than 700 kilometers.
The North later claimed through state media that it had launched a hypersonic intermediate-range ballistic missile with leader Kim Jong-un in attendance, and that the missile had a range of 1,000 kilometers.
The latest launch came four days after the South Korean government abruptly disclosed on the 8th that it had conducted the first test launch of a domestically developed hypersonic glide vehicle (HGV), a move presented as a response to a land mine explosion involving North Korean troops in the Demilitarized Zone (DMZ).