north korea’s missile success is linked to ukrainian plant, investigators say

North Korea’s success in testing an intercontinental ballistic missile that appears able to reach the United States was made possible by black-market purchases of powerful rocket engines probably from a Ukrainian factory with historical ties to Russia’s missile program, according to an expert analysis being published Monday and classified assessments by American intelligence agencies.

The studies may solve the mystery of how North Korea began succeeding so suddenly after a string of fiery missile failures, some of which may have been caused by American sabotage of its supply chains and cyberattacks on its launches. After those failures, the North changed designs and suppliers in the past two years, according to a new study by Michael Elleman, a missile expert at the International Institute for Strategic Studies.

Such a degree of aid to North Korea from afar would be notable because President Trump has singled out only China as the North’s main source of economic and technological support. He has never blamed Ukraine or Russia, though his secretary of state, Rex W. Tillerson, made an oblique reference to both China and Russia as the nation’s “principal economic enablers” after the North’s most recent ICBM launch last month.