The Trump administration has been looking for a current or former Cuban official who could be persuaded to take over the government in Havana as the United States ratchets up its pressure campaign, according to current and former U.S. officials.

The plan is more regime alteration than regime change.

The Trump administration has pressed its spy agencies to identify someone in the mold of Delcy Rodríguez, who became Venezuela’s interim president after U.S. forces captured the previous leader, Nicolás Maduro, in January.

U.S. officials viewed Ms. Rodríguez as a pragmatist who could seamlessly assume power and would be willing to work closely with them.

Some administration officials believe that a similarly pragmatic leader can be found in Cuba.

But American spy agencies have assessed that Cuba is less like Venezuela and more like Iran, according to people briefed on the intelligence reports.

There are few pragmatic officials who would be poised to take power if U.S. forces captured Raúl Castro, the former president of Cuba who still wields enormous political influence, or somehow forced out the current leadership, according to multiple U.S. officials.

Instead, the officials waiting in the wings in Cuba, like their Iranian counterparts, represent more hard-line factions.

The Trump administration has oscillated between wanting to work with Cuba’s Communist government and developing plans to overthrow it.

U.S. officials presented a list of demands to Cuban leaders in recent weeks, offering incentives if Cuba made progress.

The Trump administration wants Cuba to liberalize its economy, open up to American businesses, buy oil from the United States and push out Russian and Chinese intelligence operatives.

Few details are known about the incentives the United States has offered, but some involve providing more humanitarian aid and loosening U.S. sanctions imposed on the Cuban economy.

The current Cuban government does not appear willing, at least for now, to make those kinds of concessions, giving an urgency to the efforts to identify alternative leaders.

Cuba has announced major economic changes, allowing in more private enterprise, but the measures appear to have fallen short of what the Trump administration has demanded.

Representatives of the Cuban government did not respond to a request for comment.

The White House declined to comment. But an administration official said that while the United States is ready to open a new chapter with Cuba, the government in Havana was standing in the way of a better future.

Given the dearth of pragmatists, it is not clear whom the White House might prefer as an alternative leader.

The Cuban government appears to be supporting Oscar Pérez-Oliva Fraga, a grand nephew of Fidel Castro, as a potential successor. He has recently been more visible on state television and in government pronouncements, and even gave a rare interview to international news media.

But Mr. Pérez-Oliva Fraga would almost certainly be unacceptable to the United States. The Trump administration might be open to another Castro relative, Raúl G. Rodríguez Castro, known as “Raulito” or “El Cangrejo” (the Crab), Raúl Castro’s grandson. He long served as the former president’s bodyguard but has never held public office.

The current interior minister, Lázaro Alberto Álvarez Casas, may also be acceptable to U.S. officials.

When John Ratcliffe, the C.I.A. director, visited Cuba this year he met with both Mr. Rodríguez Castro and Mr. Álvarez Casas.

The C.I.A. has secretly established a Cuba task force, a signal that the Trump administration has set plans in motion for a more concerted pressure campaign against the Cuban government to make the changes demanded by President Trump.

U.S. and Israeli officials mulled a regime change plan for Iran when they launched their joint war more than five months ago.

At that time, Mr. Trump was obsessed with replicating the Venezuelan model in Iran, believing his administration could find a leader willing to work with the United States who might be in position to assume power after a decapitation strike against the government.

Some of the Iranian officials whom U.S. officials identified as more pragmatic were inadvertently killed in the opening strikes of the war that were aimed at killing the supreme leader, Ayatollah Ali Khamenei.

An Israeli plan that had the support of some in the U.S. government would have sought to bring Mahmoud Ahmadinejad, a former president of Iran, to power. Mr. Ahmadinejad was no moderate — while in office he called for the destruction of Israel. But after leaving the presidency, he became more and more critical of Iran’s clerical leaders. Israel began cultivating him and considering him to lead a new Iranian government.

But that plan went awry quickly. Mr. Ahmadinejad became disenchanted with the Israeli plan and ultimately left a safe house where Israel’s intelligence operatives had taken him.

In hindsight, the U.S. and Israeli strategy for regime change in Iran seemed far less planned out than the operation to grab Mr. Maduro in Venezuela.

The precise U.S. plans for Cuba remain unclear.

The U.S. government has imposed a de facto blockade on Cuba, bringing the island into crisis as energy supplies have nearly run out.

It is also not clear how far the Trump administration might go to force a leadership change. The Justice Department has unveiled an indictment of Raúl Castro. The U.S. government used an indictment of Mr. Maduro to justify the Special Operations raid that resulted in his capture.

But Mr. Maduro was the sitting president of Venezuela and his removal brought Ms. Rodríguez, who was then the vice president. In contrast, Mr. Castro, 95, holds no official office, and capturing or arresting him would not in itself prompt a leadership change.

In the months since the Maduro raid, Cuba has taken defensive measures to make it more difficult for U.S. forces to mount a raid to capture or kill Mr. Castro or the current president, Miguel Díaz-Canel, according to some American officials.

Adam Entous contributed reporting.