ROME (AFP)---The Vatican on Wednesday unveiled secret documents aimed at showing controversial pope Pius XII's attention to the persecution of the Jews and promised the full archives would be opened soon.   

The documents are part of an unprecedented exhibition in Rome of rare Vatican archives spanning centuries of history and include a report from a papal envoy on the conditions inside seven internment camps in southern Italy.   

Another document is a letter from a formerly interned rabbi in 1942 who thanks the then head of the Roman Catholic Church for sending aid to the camp including clothes and linen.   

A third document is from former Jewish detainees who met with the pope for an audience in 1944 and expressed their gratitude for his support.   

They said the pope had sent "substantial and generous gifts and demonstrated his keen and paternal interest in our physicial, spiritual and moral wellbeing" and said he had saved them from the threat of deportation to Poland in 1942.   

The Vatican's second in command, Secretary of State Tarcisio Bertone, visited the opening of the exhibition on Wednesday and said he had been most struck by the documents relating to the papacy of Pius XII.   

Bertone said the documents were part of efforts for "historical truth", adding: "The research on the period of Pius XII has so far generated more than two million files and information about prisoners of war".   

The head of the Vatican archives, Sergio Pagano, also said the full archive from Pius XII would be made available "within one or two years".   

"The final decision however depends on the pope," he told reporters.   

"Benedict XVI's willingness to accelerate the opening, also as a way of silencing dissonant voices... can only benefit the Church," he said.   

Pius XII has been put on the path to sainthood by German-born Pope Benedict XVI, 85, who briefly served in the Hitler Youth and was later drafted into the armed forces. Jewish groups accuse Pius XII of having failed to speak out against Nazi crimes.   

The Catholic Church argues that Pius in fact saved many Jews who were hidden away in religious institutions, and that his silence during the Holocaust was born out of a wish to avoid aggravating their situation.