Among the specific changes outlined by the Treasury Department are restrictions on travel to Cuba for educational or cultural exchange groups, which will now be permitted only for sponsored groups in the United States, and with the participation of representatives from those groups.
Individuals traveling for so called "people-to-people" outreach will no longer be able to visit the country, except where travel arrangements have already been made, or in cases where these individuals are accompanied by permitted, US-based sponsors, a senior administration official explained to reporters on a conference call.
"We have strengthened our Cuba policies to channel economic activity away from the Cuban military and to encourage the government to move toward greater political and economic freedom for the Cuban people," Treasury Secretary Steven Mnuchin said in a statement.
The State Department has also published a list of 180 entities including hotels, stores, rum makers, marinas and a economic development zone at the Port of Mariel, which are believed to financially benefit the Cuban military, intelligence and security services and which US citizens will no longer be permitted to frequent.
"Channeling economic activity away from entities controlled by the Cuban military will encourage the government to move towards greater political and economic freedom for the Cuban people," another senior administration official on the call asserted.
At a news conference Wednesday night, Cuban officials blasted the new regulations and said the measures would not succeed in pressuring the island's government to make concessions sought by the US.
"Let's sanction Cuba, let's impose new measures on Cuba to provoke changes in Cuba. Has it happened in the past? Never ever," said the Cuban foreign ministry's director general for US affairs Josefina Vidal. "It hasn't worked, it doesn't work, it won't work."
The US officials did not go into detail about how the list was compiled. The Four Points by Sheraton Havana, owned by the US company Starwood, is notably absent from the list, even while the Cuban holding company operating the hotel is on the list.
Asked why the hotel was left off, the first official said, simply, "we assess how listing hotels would affect the Cuban people and whether doing so advances the interests of the United States. In coordination with (the Treasury Department's Office of Foreign Asset Control), we determined it wouldn't fall into it."
A fact sheet released by the Treasury Department noted that, "Renting a room in a private Cuban residence (casa particular), eating at privately owned Cuban restaurants (paladares), and shopping at privately owned stores run by self-employed Cubans (cuentapropistas) are examples of authorized activities."
"However," it went on to say, "in order to meet the requirement of a full-time schedule, a traveler must engage in additional authorized support for the Cuban people activities."
In a statement, the group Engage Cuba -- which advocates for an end to the US embargo on Cuba -- said the regulations "create a more convoluted, confusing and counterproductive approach to Cuba policy."
In June, Trump announced he would be rolling back some of the changes made by his predecessor, Barack Obama, who sought in his second term to restore diplomatic relations with the island nation.
The changes take effect Thursday.