North Korean leader Kim Jong-un, right, looks at monitors during the launch of a missile, Jan. 11, in this photo provided by the North Korean government. The North warned Friday it will have to take a "stronger and certain reaction" after the United States slapped new sanctions on individuals there after recent missile launches. AP-Yonhap

North Korea warned Friday it will have to take a "stronger and certain reaction" after the United States slapped new sanctions over Pyongyang's recent missile launches.

In a statement carried by the official Korean Central News Agency, a spokesperson for the North's foreign ministry said the recent launch of what it claims to be a hypersonic missile was an "exercise of right to self-defense."