According to the note, "several searches are being carried out this Thursday to comply with 15 search and seizure warrants at banking institutions, at the headquarters of an association, at homes and at company headquarters.

The criminal investigation is based on facts that may "frame the practice of crimes of qualified embezzlement, money laundering and qualified tax fraud".

Portugal’s Montepio bank said that it has been the target of searches by the criminal investigation police (PJ) related to client operations and it was assisting.

"The searches of the premises took place this Thursday, January 16, according to the statement published by the attorney general's office and it is also reported that these are proceedings in respect of client operations, which relate to events that occurred between 2011 and 2014," the statement said.

The bank that belongs to the Montepio Geral Mutualist Association also indicated that it is cooperating with the authorities.

"The institution scrupulously fulfils its duties of collaboration with the authorities," it said.