China’s defense minister said any effort to challenge Beijing’s authority over Taiwan was “extremely dangerous” and called on U.S. leaders to drop what he said was a “Cold War mentality.”

Minister of National Defense Wei Fenghe made the remarks Thursday in a speech to a regional military forum in Beijing. Wei also said China opposed any efforts to launch an arms race between the world’s two largest economies.

“Taiwan is China’s core interest,” Wei said. “On these issues, it’s extremely dangerous to challenge China’s bottom line repeatedly. If anyone tries to separate Taiwan from China, China’s military will take action at all costs.”