Payá, who worked tirelessly to open more space for civil society, won the European Parliament’s Sakharov Prize in 2002 and was nominated multiple times for the Nobel Peace Prize.

He embarked on the Varela Project in 1998 and delivered the first group of more than 11,000 signatures to the National Assembly, Cuba’s parliament, in 2002. Before the petition drive was over, there were more than 25,000 names on the petition. The project took its name from Félix Varela, a priest revered for his role in Cuba’s independence fight against Spain.

Cuban authorities ignored the Varela Project petitions, but the government did launch its own petition drive, which led to enshrining the socialist system as “irrevocable’’ in the Cuban constitution.

Still, Payá, a Catholic layman, continued his efforts to mobilize Cubans to demand their civil rights although in recent years the spotlight shone more brightly on younger dissidents.

“The unexpected and tragic death of this human rights activist is certainly a blow and a setback for Cuba’s small civil society; yet, his example and his courage will continue to inspire those both inside and outside of Cuba who work and struggle for a peaceful but real transition in Cuba to a democratic form of government in which both human rights and the rule of law are protected,’’ said Miami Archbishop Thomas Wenski in a statement Monday.

A Mass in Payá’s honor is scheduled for 8 p.m. Tuesday at Ermita de la Caridad, known as the Shrine of Our Lady of Charity, in Coconut Grove. Numerous dissidents gathered Monday at Payá’s home and at El Salvador del Mundo church in the Havana neighborhood of El Cerro to pay tribute. There was a 10-minute ovation when Payá’s body arrived at the church where he launched his civic movement in 1991. He is expected to be buried Tuesday.

Miriam Leiva, a founding member of the Ladies in White dissident group, and Oscar Espinosa Chepe, a dissident economist, issued a joint statement praising Payá’s work and also demanded exhaustive and timely information from authorities on the circumstances of the dissidents’ deaths.

As word of Payá’s death spread, condolences from fellow dissidents, the Catholic Church and people around the world were extended to his wife and family.

Payá, the White House said, was a “tireless champion” in “the nonviolent struggle for freedom and democratic reform in Cuba.”

“Cuba has lost one of its most important voices of political dissent and strongest proponents of fundamental freedoms for the people of his homeland. We extend our most heartfelt condolences,’’ said Victoria Nuland, a spokeswoman for the U.S. State Department. “Mr. Payá will be remembered for his vision and dedication to a better future for Cuba. His legacy will endure in the inspiration he provided to the Cuban people and his admirers the world over.”

Republican Florida Sen. Marco Rubio called Payá “one of many heroes on the island who has exposed the myths and failures of the Cuban Revolution and challenged its habitual violation of human rights. As we try to learn more about the circumstances of Payá’s death, it is critically important that the international community join those inside Cuba in pressuring the regime to be forthcoming with the truth,’’ he said in a statement. “It’s important that anyone with knowledge about this car crash be protected and allowed to share what they know.”

El Nuevo Herald staff writer Juan O. Tamayo contributed to this report.