Air Force Secretary Frank Kendall revealed on Tuesday what he believes is the most “disturbing” thing he’s seen in a 50-year career.

Kendall said China’s expansion of its nuclear arsenal is highly concerning and every bit as much, at least, as was the dramatic expansion of the former Soviet Union’s arsenal during the Cold War.

During a hearing on Tuesday before the House Appropriations Committee, Kendall, a veteran of 50 years in U.S. military and defense, stated that China’s emergence as a top-level nuclear power is a significant concern.

“I don’t think I’ve seen anything more disturbing in my career than the Chinese ongoing expansion of their nuclear force,” Kendall told the panel.

“For decades, they were quite comfortable with an arsenal of a few hundred nuclear weapons, which was fairly clearly a second-strike capability to act as a deterrent,” Kendall continued, according to Fox News. “That expansion that they’re undertaking puts us into a new world that we’ve never lived in before, where you have three powers — three great powers, essentially — with large arsenals of nuclear weapons.”

Kendall, a graduate of the U.S. Military Academy at West Point in 1971, emphasized the need for the United States to initiate a dialogue with Russia and, in particular, China. He argued that maintaining open lines of communication was a critical factor in preventing nuclear escalation during the Cold War.

“Russia’s latest move on the New START treaty is not helping — it’s going in the wrong direction,” Kendall said. “Nobody wants a nuclear war. We do not want to go back to [the Cold War] world of 30 years ago. I thought we would never be in this position again, and here we are. So, we need to be wise. We really need to start talking to them.”

According to a report by the Pentagon, China disclosed its intentions to increase its nuclear warhead stockpile by a factor of three by 2035 in a statement made towards the end of last year.

The report, titled “Military and Security Developments Involving the People’s Republic of China,” assumes that China “probably” enlarged its nuclear program in 2021 and that its stockpiles have “surpassed 400” warheads.

“If China continues the pace of its nuclear expansion, it will likely field a stockpile of about 1,500 warheads by its 2035 timeline,” the Department of Defense assessment noted.

Kendall assured lawmakers that a war with China was not an inevitable outcome while emphasizing that maintaining a lead over China’s military capabilities was crucial to establishing deterrence, the outlet reported.