The launch occurred just two days after Seoul hosted a defense ministerial meeting with member states of the United Nations Command (UNC) to discuss strengthening security cooperation in response to North Korea's growing nuclear and missile threats.
The JCS analyzed that the missiles were fired from a site near Pyongyang around 7:10 a.m. (2210 GMT) and traveled approximately 360 kilometers (223 miles) east.
"The South Korean military has strengthened surveillance and vigilance in preparation for any further provocations," the JCS said. "We are maintaining a full readiness posture while closely sharing military intelligence with the U.S. and Japanese authorities."
The JCS denounced the launch, saying, "North Korea's missile launch is a clear act of provocation that seriously threatens peace and stability on the Korean Peninsula, and we strongly condemn it."
Thursday's launch came about two months after North Korea fired a presumed ballistic missile in early July and follows a recent test of a 240-millimeter rocket launcher on August 27.