A federal court ruled Wednesday that files compiled by the East German secret police on former Chancellor Helmut Kohl must remain largely sealed, handing Kohl a boost in a years-long legal battle.

Kohl has long argued that wiretaps used by the Stasi to spy on him were illegally obtained and that he deserves protection from damage to his"human dignity." He took the case to the Federal Administrative Court after a Berlin court ruled last year that the files could be released.

The federal court ruled that the files could be released to media"only with the consent of the person affected," except in cases where the information contained is publicly available. Files containing personal information can be released only for research purposes, on condition"that they not fall into the wrong hands or be published," it said.

The decision means that"the Stasi files on former Chancellor Helmut Kohl must remain largely sealed in future," the court said in its ruling.

Marianne Birthler, the head of the agency overseeing the Stasi archives, has fought Kohl's attempts since 2000 to keep his records private, saying that public figures must be informed on queries to view their files and have a chance to lodge a complaint, but that the former leader could not be exempt from laws applying to others.

Journalists and historians had asked to see Kohl's Stasi file, which Kohl himself has viewed, prompting speculation that they could shed light on a party financing scandal that tainted Kohl and his conservative party.

Kohl claims that the Stasi notes are bound to be full of phony information....