Javier Galeano, File, Associated Press
FILE - In this March 26, 201 file photo, a man is taken away by security as he shouts "Down with the Revolution! Down with the dictatorship!" shortly after Pope Benedict XVI arrived to Revolution Square for a Mass in Santiago de Cuba, Cuba. Cuban dissident Jose Daniel Ferrer identified the protester as Andres Carrion Alvarez, a 38-year-old resident of the eastern city of Santiago de Cuba, and that he was still in police custody as of Friday March 30, 2012.

HAVANA — A leading Cuban dissident has identified the mystery man who yelled anti-government slogans just before a Mass celebrated by Pope Benedict XVI this week before being hustled away by security agents.

Jose Daniel Ferrer told The Associated Press that the protester's name is Andres Carrion Alvarez, and identified him as a 38-year-old resident of the eastern city of Santiago de Cuba. Ferrer said the man was still in custody Friday.

The protester shouted "Down with the Revolution! Down with the dictatorship!" near journalists at the Mass at Santiago's crowded Revolution Plaza on Monday. Video of the incident showed him being hit by an apparent first-aid worker wearing a white T-shirt with a large red cross, before they were separated. Security agents quickly took him away.

Ferrer is the leader of the Patriotic Union of Cuba opposition group in Santiago. He says Carrion approached another member of the group in recent weeks and expressed interest in their activism.

"We were able to identify him this morning," Ferrer said, adding that two of his colleagues were trying to contact Carrion's family. Ferrer said Carrion was being held at the Versalles police station in the city. It was not clear if he had been charged with any crime.

The government has had no comment, but a spokesperson for Benedict said the pontiff was aware of the incident and concerned about the man's welfare.

"There was contact made to be informed about the person and his situation," the Rev. Federico Lombardi told journalists before the pope's departure Wednesday. "The interest was there and was manifested."

Benedict met with Cuban President Raul Castro and his brother Fidel during the three-day trip. He denounced the country's Marxist system as outmoded ahead of his arrival, and used homilies and speeches to urge greater freedom. He also criticized the 50-year-old U.S. economic embargo, which he said had caused unnecessary suffering.

The Santiago protester's identity had been a mystery to leading members of the island's small dissident community, with some taking to Twitter to try to find out more about him.

Elizardo Sanchez, who monitors human rights on the island and acts as a de facto spokesman for the opposition, said he had no idea who the man was. Cuba considers all the dissidents to be mercenaries paid by Washington to stir up trouble.

Andrea Rodriguez on Twitter: www.twitter.com/ARodriguezAP