Portugal's Attorney-General's office says officials are searching government offices and other locations as part of a corruption and money-laundering investigation centered on the granting of residence permits to investors from outside the European Union.

The Finance Ministry said the office of the secretary of state for tax affairs was one of 34 places searched Wednesday.

Portugal offers so-called "golden visas" to non-EU citizens who invest large amounts. More than 80 percent have been granted to Chinese citizens, and the program has brought investments totaling more than 1 billion euros ($1.1 billion).

The Finance Ministry said in a statement that Paulo Nuncio, the secretary of state for tax affairs, was questioned about sales tax on a deal between a Portuguese company and Libya's Health Ministry.

Authorities declined to provide further details.