The Trump administration on Wednesday imposed new restrictions on dealing with Cuba amid a broader toughening of its Latin American policy, limiting nonfamily travel to the island and how much money Cuban-Americans can send to relatives there, and allowing exiles to sue for property seized by the Castro government.

“In our most fervent dreams, we could not have conceived that a U.S. administration would do this,” Nicolás J. Gutiérrez, president of the National Association of Sugar Mill Owners of Cuba and whose family lost property there, said in praising the decision to allow the lawsuits. “No administration has ever done this. Forget Reagan. Forget Bush.”

By allowing the lawsuits — a departure from nearly a quarter-century of policy — the administration dismissed passionate opposition from officials in Europe and Canada who had lobbied in recent weeks against the move, which could unleash a torrent of proceedings against companies and people accused of “trafficking” in the confiscated property.

The decision, announced by Mike Pompeo, the secretary of state, was part of a broader set of policies that also targeted Venezuela and Nicaragua and were outlined in a speech in Miami by John R. Bolton, the president’s national security adviser.