A police officer waits outside the Archdiocese of Mechelen in Belgium on Thursday after a raid on the offices of the country's most senior Catholic prelate during an investigation of sex-abuse allegations. (Virginia Mayo/Associated Press)

The Vatican has stepped up its criticism of raids carried out by Belgian police investigating alleged sex abuse by priests, with the No. 2 official saying Saturday that the raids would be unprecedented even under communism.

The raids this week targeted the home and office of a retired archbishop and also the graves of two prelates.

"It is an unheard-of and very grave fact," Cardinal Tarcisio Bertone, Vatican secretary of state, said Saturday. Speaking on the sidelines of a conference in Rome, Bertone lamented that bishops were held for nine hours without food or drink.

"There are no precedents, not even in communist regimes," Bertone said, according to Italian news agencies.

The Vatican has summoned the Belgian ambassador to the Holy See to convey its anger. In a statement from Bertone's office on Friday, the Vatican said it was astonished and outraged at the violation of the tombs.

Belgian police on Thursday raided the home and former office of former archbishop Godfried Danneels, taking documents and his personal computer. Police and prosecutors did not say whether Danneels was suspected of abuse himself or simply had records pertaining to allegations against another person. He was not questioned.

Investigators also opened the graves of archbishops in the St. Rombouts Cathedral in Mechelen, north of Brussels, looking for possibly incriminating documents, according to the office of the Brussels public prosecutor.

Avvenire, the newspaper of the Italian Bishops' Conference, lamented the "brutality" of the raid on the cathedral, claiming that "there is something that goes beyond the legitimate requirements of justice."

"Does such an assault not assume a symbolic meaning, is it not the sign of a desire to attack the Church in its entirety?" the newspaper said in a front-page editorial Saturday. It said the raid "smacks of a settling of the score" with the church by a secular country.