Standing at an altar in the Plaza of the Revolution, at an open-air Mass attended by several hundred thousand of the faithful, or the merely curious, Pope Benedict XVI on Wednesday appealed to Cuban authorities for greater freedom for the Catholic Church here and asked specifically that the government allow religion to be taught in schools and universities.

It was a day of dueling symbols and a diplomatic push and shove between the pope and his Communist hosts.

There was the pope, celebrating Mass before an audience filled with committed atheists. Across the plaza, there was the towering image of Che Guevara, urging his fellow revolutionaries to march always toward victory.

After the Mass, the pope met with Fidel Castro at the Vatican Embassy, where the ailing former leader quizzed Benedict about the changes in the Catholic liturgy since the long-ago days when Fidel was an altar boy, educated by Jesuits.

According to a Vatican spokesman, the pope raised issues of freedom and liberty with Castro. The Vatican described the meeting as “intense” but “cordial.”

The Mass was attended by President Raul Castro, who sat in the front row surrounded by high-ranking government officials as the pope delivered a sermon warning against those who “close themselves up in their own truth and try to impose it on others.”

The pontiff said that such sinners are driven by “irrationality and fanaticism” and that they are “like the blind scribes who, upon seeing Jesus beaten and bloody, cry out furiously, ‘Crucify him!’ ”

In that passage, the pope did not mention Cuba or its government, and it was left to the audience here and around the globe to interpret the message.

If it was a dig at the current leadership, as some analysts suggested afterward, the point was lost on many in the crowd.

Based on interviews after the Mass, most people did not think the pope was talking about the Castro brothers or their socialist revolution. Indeed, many in the audience had never attended church and did not understand the use of parables.

“It was a speech about love and the unity of all Cubans,” said Yoan Danilo, a student from the elite University of Computer Sciences, who said he was not a believer.

“I think it was beautiful, a message of solidarity with the Cuban people,” said Juana Ramirez Gomez, who, like many in the crowd, said she was an atheist but had come out of respect for the pope as a head of state and a messenger of peace.

Some of those who filled the sunny square said they came to the Mass because their employers, teachers or neighborhood party organizers required attendance and were taking a roll call.

At the edges of the crowd, some young people lounged on the ground, yawning, smoking or talking during the service. After the homily, midway through the Mass, people began to head for the exits in a steady stream.

For some reason, cellphone service in Havana was interrupted during the Mass. Some of Havana’s dissidents told the Associated Press that their members had been detained.

Despite pleas from dissidents who had hoped to raise their profiles and confront Cuban authorities more directly, the pope did not meet with any opposition figures.

The Cuban government made Wednesday a paid holiday for state workers, and some were encouraged to appear at the Mass or at assigned spots along the pope’s route to wave flags. A lot of others headed to the beach.

But it is also true that many of Cuba’s faithful were moved by the chance to see the pope and hear his words.

“It is a lie that we cannot practice our faith in Cuba. We can. We can. Not with complete freedom, not yet, but we survive,” said Andres Diaz, a retired engineer and a Catholic.

Diaz said the church in Cuba was teaching its flock to “be tolerant, patient, to open our hearts to each other, but most important, to not be afraid anymore.”

Asked what he meant by that, Diaz said the church was giving people the courage to criticize the social and economic realities of Cuba and to push for change.

The 84-year-old pontiff, reading in Spanish, reiterated the theme of his three-day trip to Cuba, urging liberty and freedom.

“Cuba and the world need change, but this will occur only if each one is in a position to seek the truth and chooses the way of love, sowing reconciliation and fraternity,” he said.

During his homily, the pope also spoke of a search for an “authentic freedom” but was not more specific.

The pope and the Cuban government engaged in some sparring during the visit. On his flight to Mexico, before his arrival in Cuba, Benedict told reporters on his plane that Marxism is “irrelevant for today’s reality.”

Cuban leaders pushed back. At a news conference Tuesday, the government minister in charge of economic reform, Marino Murillo, said, “In Cuba, there will not be political reform.”

In his sermon at the Plaza of the Revolution, Benedict praised Cuba’s opening to the church — and then asked for more.

“It must be said with joy that in Cuba steps have been taken to enable the church to carry out her essential mission of expressing her faith openly and publicly,” the pope said. “Nonetheless, this must continue forwards, and I wish to encourage the country’s government authorities to strengthen what has already been achieved.”

Specifically, Benedict asked for freedom to teach religion in the schools. In Cuba, the church can teach catechism in classes at church but cannot operate its own schools.

During a meeting Tuesday with Raul Castro, Benedict asked that the government declare Good Friday a holiday. After Pope John Paul II came to Cuba in 1998, the state declared Dec. 25 a holiday.

Before his departure at the Havana airport, the pope pleased Cubans by chiding the United States for its 50-year trade embargo against the island, which he said “unfairly burdens its people.”

“The present hour urgently demands that in personal, national and international co-existence we reject immovable positions and unilateral viewpoints which tend to make understanding more difficult,” he said.