​In recent months, Washington and its allies have expanded their joint military drills to help guard against North Korea’s growing nuclear and missile threats. They plan to conduct a Proliferation Security Initiative exercise on Wednesday, when their navies will practice interdicting vessels carrying materials for weapons of mass destruction to and from countries like North Korea. Last week, the American and South Korean militaries also started the first of a series of live-fire drills planned until mid-June near the border with North Korea.

The “dangerous military acts by the U.S. and its vassal forces” compel North Korea to secure “a reliable reconnaissance and information means,” Ri Pyong Chol, vice chairman of the North’s Central Military Commission, said on Monday, revealing the plan to launch the North’s “military reconnaissance satellite No. 1.”

North Korea’s space and ​ICBM programs are closely interlocked.

In 2012, months after Mr. Kim took power, North Korea launched a rocket that it said carried a satellite. In a major embarrassment to ​the young leader, the rocket disintegrated moments after launching. But eight months later, another North Korean rocket flew as far as the Philippines. North Korea last claimed to have launched a satellite in 2016, when its rocket also flew over the sea near the Philippines.

None of these rockets were believed to be carrying a sophisticated satellite. But their launches showed that the North was making progress in building a rocket powerful enough to carry a satellite into orbit or a warhead on an intercontinental range.