Americans won’t be able to visit Cuba without meeting tight new guidelines, making good on President Trump’s June pledge to restrict tourism and trade with the authoritarian island, the White House said Wednesday.

But administration officials are still fighting doubt about the government's enforcement of the new rules.

A Treasury Department official said “when we’ve seen violations, we’ve gone after those violators," but sidestepped a question on whether there would be additional agents hired for enforcement.

The official said during a White House conference call with reporters that “the repercussions are the same as they have been” and “for willful violations, that can be referred for a criminal prosecution.”

The Treasury Department’s Office of Foreign Assets Control for decades policed a near-total ban on U.S. travel to the island. Hundreds of thousands of Americans flew to third countries and then into Cuba, and avoided penalties with removable entry visas attached with a staple.

Tourists caught without an accepted justification — such as journalism, education, or humanitarian purposes -- generally faced a fine. After President Obama oversaw a 2014 thaw in relations, many U.S. airlines began direct flights to Havana.

“I wouldn’t expect to see OFAC at every border point, but I think we can rely -- as we relied in the past -- on interagency colleagues in customs, border control, all the agencies that supply us information,” the Treasury Department official said.

New rules for visits say individual person-to-person travel won’t be a valid justification for travel, nixing one low-bar justification. Allowable person-to-person travel must now be done under the umbrella of an actual organization.

Another nebulous category of allowed travel to Cuba, “Support for the Cuban people,” is being tightened to require “a full-time schedule of activities that result in meaningful interaction with individuals in Cuba,” though it’s not clear how this will be evaluated. One official on the call said staying at private Cuban residences will be one factor to evaluate compliance, but “that alone won’t be enough.”

More than 80 hotels, meanwhile, will be placed off-limits to Americans for alleged connection to the Cuban armed offices or intelligence agencies -- part of a parallel effort to tighten rules for U.S. businesses doing work there.

In his June speech announcing a partial reversal of Obama policies, Trump stressed political rights for Cuban citizens.

One official on the White House call Wednesday said the new rules have "nothing" to do with recent "acoustic incidents" that caused U.S. diplomats to suffer mysterious ailments.

An official on the call said that the new rules do not alter the status quo for American tourists who wish to bring home small amounts of rum and cigars, which became allowed under Obama. The rules, which take effect this week, also will not affect pre-arranged business agreements or travel plans, officials said.