The Bush administration says it hopes former President Jimmy Carter, in what will be an unprecedented visit to Cuba next week, will press the communist government there for democratic reforms. Mr. Carter will be the most prominent American to visit Cuba since the 1959 revolution that brought Fidel Castro to power.

Mr. Carter has long been a critic of the U.S. economic embargo against Cuba which the Bush administration strongly supports. And officials here are stressing that he is going to Cuba on a private mission and not as an administration envoy, either officially or informally.

At a briefing, State Department spokesman Richard Boucher noted that the former president has been a strong supporter of democracy and human rights in his world-wide travels. He said he hopes that while in Cuba, Mr. Carter delivers a "direct and straight-forward message" that it's time for a "rapid and peaceful transition to democracy" on the communist-ruled island.

"We think it's time for the Cuban government to stop the repression and violation of human rights," the State Department spokesman said. "Cuba should no longer be the exception in the hemisphere, but rather should join the inter-American community of open market democracies. We also hope that President Carter will visit the political opponents of the regime, call for the release of the hundreds of political prisoners held by the Cuban government - their only offense is to insist upon the human rights for the Cuban people - and to call for a peaceful dialogue between the Cuban government and its citizens."

Mr. Carter, who was president from 1977 to 1981, says he plans to meet with Cuban human rights activists and religious figures along with representatives of the Castro government.

The Cuban president said last month Mr. Carter will get a complete look at Cuban society and will be free to make all the criticisms he wants because, as Mr. Castro put it, "we are so convinced" of the "political and human strength of our revolution."

In what was seen as a gesture in advance of the Carter visit, the Castro government last week freed Vladimiro Roca, a democracy activist considered the country's most prominent political prisoner. He was released two months early after serving most of a five-year sentence for sedition.

During the Carter presidency, the United States, which severed relations when Mr. Castro took power in 1959, established the lower-level "interest section" diplomatic representation that continues today.

Mr. Carter's term also included the 1980 "Mariel Boatlift" crisis, which saw the chaotic exodus to the United States of some 125,000 Cuban emigrants.

Mr. Carter is due to arrive in Cuba Sunday for a visit spanning six days.