WASHINGTON — Former Secretary of State Henry Kissinger warned that if America and China let North Korea keep its nuclear weapons, it will spur other countries to seek them.

“If North Korea still possesses a military nuclear capability in some finite time, the impact on the proliferation of nuclear weapons might be fundamental,” Kissinger said in testimony before the Senate Armed Services Committee on Thursday.

“Because if North Korea could keep its capability in the face of opposition by China and the United States, and the disapproval of the rest of the … world, other countries will also feel this is the way for achieving international prominence and the upper hand.”

South Korea and Japan will want nuclear weapons too, “and then we are living in a new world ... that will require new thinking,” Kissinger said.

That sort of proliferation would represent a new pattern, effecting America’s ability to deter other countries’ use of nuclear weapons.

Pyongyang poses the “most immediate challenge to international peace and security,” Kissinger warned in written testimony. The denuclearization of North Korea, “must be a fundamental objective.”

He cautioned against a unilateral, preemptive U.S. war with North Korea on the doorstep of Russia and China, but said America will, “soon hit that fork in the road” which will require, “some prayerful thinking.”

“The temptation to deal with it with a preemptive attack is strong, and the argument is rational,“ Kissinger said. “I would be very concerned by a unilateral American war at the borders of China and Russia in which we are unsupported by a significant part of the world.”

The goal, he said, should be to enlist China in using sanctions to pressure North Korea into giving up its nuclear weapons.

The idea of halting North Korean missile tests in exchange for abandoning allied military exercises would encourage further demands to dismantle alliances in the region, Kissinger said.

“That would equate legitimate security operations with activities which have been condemned by the U.N. Security Council for decades,” Kissinger said, adding: .

Kissinger testified with fellow luminaries, Reagan administration Secretary of State George Schultz and Richard Armitage, a former deputy secretary of state under President George W. Bush.