A view of the test-fire of Pukguksong-2 guided by North Korean leader Kim Jong Un on the spot, in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang February 13, 2017. KCNA/Handout via Reuters The US military goes on high alert every time North Korea conducts another missile test, because it never knows when the big one might be coming, according to the general in charge of America's nuclear arsenal.

"Those are very concerning moments to me. Because we're not sure — every time they launch we're not sure if this is a threat missile or not," Air Force Gen. John Hyten, commander of Strategic Command, told Congress Tuesday.

"That is the definition of unpredictable," Hyten said in testimony before the Senate Armed Services Committee. "What I am concerned about most nights is North Korea."

The four-star commander said military personnel at three separate commands pull out all the stops to make an immediate determination whether a North Korean missile poses a threat to the US or its allies in the region.

"The whole network comes up," Hyten said. "We bring the entire power of my command to bear on the problem."

North Korean missiles launches are analyzed in real time by Strategic Command in Omaha, Northern Command in Colorado and Pacific Command in Hawaii.

Hyten pointed to a Feb. 11 North Korea launch as particularly worrisome because it tested a new solid-fuel intermediate range missile, launched from new mobile launcher.

That shows a technological advance that would allow North Korea to launch an intercontinental ballistic missile on very short notice.

"All those things bring the time of warning down to a very small number," Hyden said.

U.S. Air Force General John Hyten, Commander of U.S. Strategic Command, testifies in a Senate Armed Services Committee hearing on Capitol Hill in Washington Thomson Reuters

As the commander of America's nuclear arsenal, Hyten's job includes providing the president with options to use nuclear weapons if that should ever become necessary.

While saying he is a military officer, not a diplomat, Hyten called for more engagement with North Korea, and agreed with President Trump that China holds the key to deescalating the growing nuclear crisis on the Korean peninsula.

"I look at it from a strategic perspective, and I can't see a solution that doesn't involve China," he said.

The four-star general also called for continued investment on missile defense and said some new technologies offer promise to give the US capability to shoot down an ICBM in the boost phase, something currently the US cannot do.

"I can't think a better thing than if somebody launched a threat missile, to drop it right back on their head."