WASHINGTON—The Trump administration is moving deliberately to counter what the White House views as years of unbridled Chinese aggression, taking aim at military, political and economic targets in Beijing and signaling a new and potentially much colder era in U.S.-China relations.

In the first 18 months of the administration, ties between the world’s two biggest powers were defined by negotiations over how to restrain North Korea and ways to rebalance trade. Those high-profile endeavors masked White House preparations for a more hard-nosed stance with Beijing—a strategy now surfacing as China’s help with Pyongyang wanes and trade talks stall.

Interviews with senior White House officials and others in government make clear that recent volleys in what appears a new Cold War aren’t the exception to President Trump’s China policy. They are exactly what the administration wants—putting the spotlight on a meeting between Mr. Trump and Chinese President Xi Jinping at a multilateral summit planned for November.

Vice President Mike Pence last week gave a blistering speech on U.S.-China relations, saying “the United States has adopted a new approach to China” with the message to China: “This president will not back down.”

On Wednesday, the Treasury Department announced new rules targeting China that tighten national security reviews of foreign investment. On the same day, the Justice Department said it had brought a Chinese intelligence operative arrested in Belgium to the U.S. to face charges he conspired to steal trade secrets from GE Aviation and others. It was the first time prosecutors publicly identified someone in custody as a Chinese intelligence officer.