The Belgian civil law-enforcement authorities seized documents and other potential evidence related to allegations of sexual abuse after searching the headquarters, the home of a recently retired cardinal and the offices of a commission established by the church to handle abuse complaints. The grave was opened at the St. Rombouts Cathedral, north of Brussels, Jean-Marc Meilleur, a spokesman for the prosecutor’s office in Brussels, told The Associated Press.

The aggressiveness of the raids — coming after hundreds of complaints of sex abuse had been lodged with the Belgian church’s special commission within a few months — represented a major departure in Belgium’s investigation of church-related sex crimes.

In the raid on the church headquarters, at the imposing palace of the archbishop of Mechelen-Brussels, the police questioned all the bishops attending the meeting, as well as staff members, including cooks and drivers.

The Vatican’s Friday statement, which was signed by two deputy secretaries of state and the ambassador of the Holy See to Belgium, raised the prospect that victims’ confidentiality had been breached by the seizure of documents relating to abuse allegations.

Eric de Beukelaer, a spokesman for the Belgian archbishop, André-Joseph Léonard said the raids began about 10:30 a.m. Thursday.

“The police came in and said the house would be searched because there were complaints about sexual abuse on the territory of the archdiocese,” he said, adding that he was present during the raid and that the police had temporarily confiscated his cellphone.

The search continued past 7 p.m., Mr. de Beukelaer said. No arrests were made, and no charges were announced. The Associated Press reported that the bishops had been prevented from leaving and even from making phone calls.

The authorities are investigating accusations that Belgian clerics sexually abused children, according to officials. Hundreds of such claims have been raised since April, when the bishop of Bruges, Roger Vangheluwe, admitted to molesting a boy and resigned.

This sort of activity “is extremely rare, very rare, especially in the house of a cardinal,” said Andrea Tornielli, a Vatican expert at Il Giornale, an Italian daily newspaper. “It’s enormous.”

Although the raids took place during a meeting of senior clerics, a spokesman for the Brussels prosecutor’s office, Jean-Marc Meilleur, said the timing was a coincidence.

The leader of the commission founded by the church to handle abuse complaints, Peter Adriaenssens, criticized the police for taking all the records the commission had accumulated, saying he was “appalled” by the raid, reported a Dutch Web site, Het Nieuwsblad.

At a news conference Thursday afternoon, Mr. Adriaenssens, a child psychiatrist who is a leading Belgian expert on child abuse, said some people who had contacted the commission had done so in confidence and were now worried about who would have access to their statements. He said the commission had been inundated with calls and e-mail messages from those who had made complaints about abuse.

“We have no idea why this was done,” he said. He added that his impression was that “in recent months a form of paranoia has developed.”

Cases of sexual abuse of minors have added resonance in Belgium because of the notorious Belgian pedophile Marc Dutroux, convicted six years ago of child murder, kidnapping and rape. Government officials came under sharp criticism for mishandling the Dutroux case, and that controversy could account for the aggressive response.

Barbara Dorris, outreach director for the Survivors Network of Those Abused by Priests, said in a statement that the raid was “precisely what’s needed, not just in Belgium but in other church offices across the globe.”

Ms. Dorris added, “Police and prosecutors need to step up, and promptly and thoroughly investigate allegations against predator priests and corrupt bishops, and use their full powers to gain access to and control over church records that likely document the crimes and cover-ups.”

The RTL television station in Belgium reported the raid on the home of Cardinal Godfried Danneels, who retired in January as archbishop of Mechelen-Brussels. The cardinal’s computer was removed, RTL said. Mr. Tornielli, the Vatican expert, said that to the best of his knowledge, the cardinal would have diplomatic immunity as a Vatican official, and would have to have given permission for a police search of his home.