LISBON — Luiz Felipe Scolari, the coach of Brazil’s national men’s soccer team, is the subject of a criminal investigation in Portugal, authorities said Wednesday, an unwelcome distraction for the country as it prepares to host the World Cup.

Officials would not say what the investigation was about. In Portugal, continuing investigations fall under the country’s judicial secrecy law.

The Portuguese attorney general’s office said in an email to The Associated Press that the Department for Criminal Investigation and Prosecution had opened an inquiry into Scolari, but it provided no further details.

Unconfirmed reports in Brazil and the Netherlands say Scolari is suspected of failing to declare millions of dollars in income, but he has denied any wrongdoing.