Secretary of Homeland Security John Kelly said Sunday that he believes President Trump will be dealing with a nuclear North Korea capable of striking America by the end of his first term.

Kelly's statement came during an interview in which CNN's Dana Bash asked Kelly about a recent Los Angeles Times article, which said that, despite $40 billion in spending by the Pentagon, missile defense systems meant to defend against a nuclear strike by North Korea or Iran failed six times out of nine in simulated attacks tested since 2004.

"Is the U.S., at this point, capable of shooting down a North Korean missile if it were headed towards California or anywhere else in America?" Bash asked.

Kelly declined to comment specifically, insisting that any knowledge he had on the issue was classified. But Bash pushed him: in his capacity as Homeland Security secretary, could Kelly say for sure whether or not the homeland was safe?

Kelly initially demurred, making clear that Americans were necessarily at risk from some countries.

"Clearly, there are countries on the planet that have a lot of nuclear weapons that would overwhelm any defense that we would deploy," he said. "Russia, as an example."

But, when it came to North Korea, Kelly was unequivocal about the risk that a North Korean nuclear missile posed to the U.S.

"The minute North Korea gets a missile that could reach the United States, and put a weapon on that missile, a nuclear weapon," Kelly said, "the instant that happens, this country is at grave risk."

Bash asked the obvious follow-up question: How far away did Kelly think that possibility was?

"I think Mr. Trump will be dealing with this in real terms before he starts his second term," he said.

Kelly's comment comes as tensions heighten between the U.S. and North Korea over the rogue state's nuclear program.