SEOUL, Sept. 22 (UPI) — North Korea tested a new weapon system apparently involving an upgraded hypersonic missile over the weekend, state-run media reported Tuesday, as leader Kim Jong Un warned the advance would give his enemies an “incurable headache.”

The North’s Missile Administration successfully tested a “new-type weapon” Sunday, according to the official Korean Central News Agency.

KCNA did not identify the system in its written report, but a monitoring screen visible in state media photographs displayed the words “Hwasongpho-11Ma-1 flight trajectory,” Yonhap News Agency reported. The designation has been associated in previous reports with a new North Korean hypersonic missile.

Hypersonic weapons travel at least five times the speed of sound and are capable of maneuvering in flight, making them more difficult to detect and intercept than conventional ballistic missiles.

Kim oversaw Sunday’s test with his daughter, Ju Ae, who has increasingly appeared alongside him at major military events. South Korea’s National Intelligence Service told lawmakers earlier this month that Ju Ae, believed to have been born in 2013, appears to be in the process of being designated as her father’s successor.

Kim called the test “undoubtedly a striking demonstration of ultra-modern defense technology and clear progress in the modernization of the armed forces,” according to KCNA.

“To acquire such a technology is of weighty significance in the state’s readiness for war and the future development of the armed forces,” he said.

Kim added that the technological advance would deliver “a very cruel and unavoidable blow” to North Korea’s enemies.

South Korea’s military said Sunday it detected two short-range ballistic missiles launched approximately three hours apart from the Wonsan area on North Korea’s east coast.

The first missile flew approximately 280 miles, while the second traveled more than 370 miles, Seoul’s Joint Chiefs of Staff said.

However, data visible on the monitoring screen in state media photographs showed a flight distance of 564 miles, a maximum altitude of 22 miles and a speed of roughly 4,800 mph.

JCS spokesman Jang Do-young said Tuesday that South Korean and U.S. authorities were conducting a detailed analysis of the North’s claims.

Jang cautioned that North Korea’s reports about its weapons capabilities “cannot be 100% trusted.”

The test came ahead of a busy week of international diplomacy. The annual General Debate of the U.N. General Assembly begins Tuesday in New York, while U.S. President Donald Trump and Chinese President Xi Jinping are scheduled to meet Thursday in Washington.

Trump has made a series of recent overtures to Kim, including scaling back the annual Ulchi Freedom Shield exercise with South Korea last month in an effort to create conditions for renewed talks.

South Korea’s National Intelligence Service told lawmakers earlier this month that a Trump-Kim summit should be considered possible “at any time,” citing signs of movement toward dialogue, although it said no direct contact between Washington and Pyongyang had been confirmed.

Pyongyang has shown little interest in engaging so far. Kim Yo Jong, the North Korean leader’s powerful sister, last month dismissed the reduction in the allied exercise as “unworthy of comment.”