[UPDATED NOV. 8, 2017]

A little over a month after the Trump administration warned Americans not to visit Cuba because of mysterious sonic attacks, the Treasury on Wednesday published new restrictions on American travel to the island and placed dozens of military-owned hotels and shops off-limits.

Under the new rules, Americans will no longer be permitted to visit Cuba on individual “people-to-people” trips, a popular mode of travel that has fueled a boom in home rentals and family-run restaurants since President Barack Obama loosened restrictions on travel to Cuba two years ago.

They will also be barred from “direct financial transactions” with a long list of restaurants, shops and hotels that form part of the Cuban military’s extensive business empire. They include many properties in Old Havana and the five-star Gran Hotel Manzana Kempinski, whose opening last year was expected to usher in a new era of luxury travel.

Bob Guild, the president of Mar Azul Charters, a travel company that has organized trips to Cuba for many years, said the shift under President Trump was “part of a long, long history of cracking down.”