This photo shows the test-firing of a new intermediate-range hypersonic ballistic missile, provided by North Korea's official Korean Central News Agency, Jan. 7. Yonhap

Acting President Choi Sang-mok on Tuesday condemned North Korea's launch of an intermediate-range ballistic missile (ICBM) earlier this week, pledging a firm response based on the strong South Korea-U.S. alliance.

On Monday, South Korea's military reported that the North fired a suspected hypersonic missile into the East Sea, marking its first provocation of the year, just ahead of U.S. President-elect Donald Trump's inauguration.

"North Korea's missile launch is a clear violation of U.N. Security Council resolutions and represents a serious threat to the security of the Korean Peninsula and the world," Choi said while presiding over a Cabinet meeting.

Earlier in the day, North Korea also announced that it had successfully test-fired a new ICBM equipped with a hypersonic warhead, claiming the missile system would effectively deter any rivals in the Pacific region.

"Our government will firmly respond to North Korea's provocations based on the solid South Korea-U.S. alliance," Choi said.

The latest missile launch also marked the first provocation since Choi, deputy prime minister for economic affairs, took over the leadership role following parliament's impeachment of former acting President Han Duck-soo last month.

Choi directed the defense ministry to revitalize the military's organizational atmosphere and establish a robust security posture to deal with any further provocations by North Korea. (Yonhap)