Berlin - The historically rare decision of Pope Benedict XVI to retire rather than serve until his death won him the respect from clerics and politicians in major Catholic countries on Monday.

Spanish bishops felt “affected and as if orphaned by this decision that fills us with pain,” said Cardinal Antonio Maria Rouco Varela, head of the Spain's conference of bishops.

The country's ruling People's Party expressed “all its respect” for the pope's decision.

The pope said his advanced age had had an impact on his faculties “and this says it all about the human dimensions of his holiness,” said Dolores de Cospedal, secretary-general of the Christian-conservative party.

In Benedict's homeland, Germany, Chancellor Angela Merkel said it was understandable that the pope was grappling with the burden of old age in an era when people live longer and longer.

“As federal chancellor, I thank him for his work and wish him all the best for the coming years,” she said.

She acknowledged his role as a leading religious thinker, as well as his efforts to reach out to Jews and Muslims.

The World Jewish Congress honoured Benedict's many contacts with the Jewish community and his steps to censure extremist Catholic Holocaust deniers.

“No pope before him made more strides to improve the relationship with the Jews - on so many levels,” the organization's president Ronald Lauder said in New York.

Italian president Giorgio Napolitano said Benedict had shown “extraordinary courage and an extraordinary sense of responsibility,” when he made his decision.

Church leaders in various countries also said they were surprised by the pope's step.

“This was like a lightning from the sky. There was absolutely no information in the last days hinting it might come to this”, said Jozef Kloch, spokesman of the Polish Catholic bishops conference.

Adam Boniecki, a leading Polish Catholic intellectual, said Benedict probably wanted to avoid a repetition of the last months of his predecessor John Paul II, which were marked by the Polish pope's failing health.

“We have to be grateful that Benedict showed how to solve the problem of the (pope's) office, weakness and old age in great faith,” he said.

Reporters immediately began speculating about possible successors.

Austrian broadcaster ORF asked Austria's Cardinal Christoph Schoenborn about his prospects, since the clergyman had been counted among possible papal candidates ahead of Benedict's election.

“My heart is in Vienna and in Austria, but of course my heart is also with the entire church,” 68-year-old Schoenborn said, when asked about the upcoming conclave, the meeting of cardinals to choose a new church leader.

The Philippines prayed that the Catholic Church “will emerge from the coming period of the Sede Vacante, the conclave to come, with the election of a new pope prepared to take up the great burdens and expectations of the Catholic faithful worldwide,” the country's presidential spokesman Edwin Lacierda said.

Asia's largest predominantly Catholic country had been touched by the pope's work, he said. “May he find respite from his physical challenges, and peace and contentment in the seclusion of retirement,” he added. - Sapa-dpa