Four projectiles were launched from an area near the North's Dongchang-ri long-range missile site at 7:36 a.m. and flew about 1,000 kilometers before splashing into the East Sea.

"North Korea's nuke and missile provocations are real and imminent threats for the people's lives and security," Hwang said.

It marks the first time for him to hold an NSC meeting at the presidential office after becoming acting president.

Hwang said considering the brutality of the North Korean regime as shown in the latest killing of Kim Jong-nam, there would be unimaginable consequences if Pyongyang actually obtains nuclear weapons.

The acting president requested the military to maintain full alert under the Seoul-Washington alliance to tackle North Korean provocations. Hwang also highlighted that South Korea should promptly complete the deployment of an advanced US missile defense system in the country.

"We need to complete the deployment of the Terminal High Altitude Area Defense battery promptly, and establish a defense system against North Korean nukes and missiles," Hwang said. 

While South Korean plans to complete the deployment of the battery this year, the project has been facing challenges due to strong protest from Beijing, which expresses concern the THAAD system will have an adverse impact on its military strategy. (Yonhap)