One of Bolsonaro's closest aides, Mauro Cid, has been arrested in the same operation, the sources added.

Federal police earlier in the day said in a statement they were serving 16 search and seizure warrants and six preventive arrest warrants in Brasilia and Rio de Janeiro as part of the operation, but did not disclose the names of those targeted.

Police said the "false data" were added to the database between November 2021 and December 2022, when Bolsonaro was president, to alter immunization statuses of still unnamed people.

A spokesman and a lawyer for Bolsonaro did not immediately respond to requests for comment.

(Reporting by Lisandra Paraguassu; Editing by Steven Grattan)

By Lisandra Paraguassu and Ricardo Brito