Former Secretary of State and National Security Adviser Henry Kissinger said the U.S. and China, embroiled in a trade war for a year and a half now, are in the “foothills of a cold war,” and that it will be worse than World War I if things continue down this path.

“That makes it, in my view, especially important that a period of relative tension be followed by an explicit effort to understand what the political causes are and a commitment by both sides to try to overcome those,” Kissinger said during the New Economy Forum. “It is far from being too late for that, because we are still in the foothills of a cold war.”

Kissinger said China and the U.S. now are much bigger than Russia and the U.S. during the first Cold War, and that the world’s two biggest powers and two biggest economies “are bound to step on each other’s toes all over the world, in the sense of being conscious of the purposes of the other.”

“So a discussion of our mutual purposes and an attempt to limit the impact of conflict seems to me essential,” said Kissinger, 96, the former Secretary of State under Richard Nixon. “If conflict is permitted to run unconstrained the outcome could be even worse than it was in Europe. World War 1 broke out because a relatively minor crisis could not be mastered.”

Kissinger said while the two sides are negotiating trade, that would be a good time to begin political discourse.

“Everybody knows that trade negotiations, which I hope will succeed and whose success I support, can only be a small beginning to a political discussion that I hope will take place,” he said.

Hours before Kissinger spoke, Chinese Vice President Wang Qishan said his country is committed to peace.

“Between war and peace, the Chinese people firmly choose peace. Humanity cherishes peace,” he said. “We should abandon the zero-sum thinking and cold war mentality.”

Meanwhile, the U.S. and China are still ironing out the final parts of “phase one” of a trade deal between the countries.