His comments indicate that the United States possesses enough information to target not only North Korea's missiles but also the support facilities that allow a launch in a potential attack on the United States.
"Remember, missile infrastructure is not just the missiles," Selva said at a roundtable with journalists in Washington. "If you're the poor sergeant that has to go out and launch the missile, and I blow up your barracks, you're not available to go do your job."
North Korea has been advancing rapidly toward the possession of an intercontinental ballistic missile (ICBM) that could land a nuclear warhead on the continental United States, posing one of the most critical national security threats the Trump administration faces.
Pyongyang conducted its first ICBM test in July and tested two more by the end of last year. The country also tested in September a nuclear weapon that a top U.S. general later said he assumed was a hydrogen bomb.
Despite the significant strides, North Korea has not yet successfully tested all the components necessary to show the world it possesses an ICBM capable of delivering a nuclear warhead to a target in the U.S. mainland, Selva said.
Kim's tests have shown that his missiles can travel far enough to reach the United States and maneuver stably in the right direction, according to Selva. But the North Korean leader has yet to demonstrate a "terminal guidance system" that allows for the specific targeting of the missile and a "reentry vehicle" capable of withstanding the stress and shock that comes with carrying a nuclear warhead back through the Earth's atmosphere to a target, the general said.
Selva did not rule out that North Korea already possesses those technologies but said the country has not demonstrated them.
"It is possible, although I think unlikely, that he has found a way to do the test without us knowing," Selva said. "But I can't envision what that test would look like, where he would be convinced that he has those components at a reliable-enough level of performance to declare that he's ready."
CIA Director Mike Pompeo said in an interview Monday with the BBC that the United States and its intelligence partners have developed a pretty good understanding of North Korea's nuclear capabilities.
"We talk about him having the ability to deliver a nuclear weapon to the United States in a matter of a handful of months," Pompeo said.
The United States has been stepping up pressure on North Korea through sanctions with the hope of bringing Kim into negotiations about dismantling his nuclear program. The North Korean leader has rejected the idea.
Russia and China have proposed a "freeze for freeze," whereby the United States and its regional allies would stop military drills in exchange for a halt on North Korea's tests.
The Trump administration, however, has rebuffed any such proposal. Secretary of State Rex Tillerson said Jan. 16 in Vancouver that Washington rejected such an approach because it falsely equates legitimate defensive military actions by the United States and its allies with unlawful actions by North Korea.
Asked about the possibility of pursuing a "freeze for freeze," Selva said the decision was up to the U.S. officials leading diplomacy with North Korea.
"I'm not in charge of the diplomatic effort," Selva said. But he added that the current situation — in which North Korea has not yet crossed the finish line in its quest — presented "an opening to have that conversation."
Selva declined to rule out the possibility of a preemptive strike on North Korea's weapons facilities but suggested that preemption is not generally how the U.S. has approached nuclear-armed adversaries.
"We don't do preemption," Selva said. "Our method of warfare: If they launch one, then game on. But preemption is not something we do as a matter of course."