Seoul defense officials say North Korea has fired at least four rockets from "multiple rocket launchers" into the Yellow Sea.
Pyongyang has fired a "set of banned weapons" this year and tested a set of reconnaissance satellites that Seoul and Washington have described as an intercontinental ballistic missile system, Reuters reported.
The Joint Chiefs of Staff of the South Korean Armed Forces told reporters in a message:
There were shootings that may have been fired this morning (Sunday) by multiple North Korean rocket launchers. Our army maintains its defense readiness and at the same time closely follows the relevant developments.
Four shots were fired in one hour from 7:20 a.m. Sunday local time (1:50 a.m. Sunday, Tehran time) from an unknown location in South Pyongyang province, Yonhap News Agency reported, citing South Korean officials. The target of the shootings is under investigation.
South Korea's National Security Council held an emergency meeting after the shootings and called for a stronger defense to end the "security vacuum during the transfer of power in the South Korean government."
The North Korean test came a day before the U.S. military launched a provocative exercise in and around the Korean Peninsula to demonstrate its opposition to Pyongyang missile tests.