BUENOS AIRES, Argentina (AP) _ Employees at the national mint made illegal copies of Argentina's currency and government bonds in a scheme that may have netted millions of dollars, officials said Thursday.

Economy Minister Nestor Rapanelli said it was too soon to give an estimate of how much money was involved.

In a radio interview, Vice President Eduardo Duhalde said the bills and bonds are illegal duplicates but not counterfeit. He said they are legal currency.

Six people were being questioned, including Eduardo Alejandro Petronzi, director of the mint's chemical lab. No charges were immediately filed, according to Carlos Branca, a federal judge.

The alleged fraud, which was discovered earlier this year, may have begun as far back as 1987, Branca said. He said the state intelligence service and the federal police were investigating.

The independent news agency Diarios y Noticias, citing unidentified government sources, said mint employees stole paper and chemicals, and simply printed additional copies of legitimite bills and bonds.

The scheme came to light when different provincial bonds bearing the same certification numbers were discovered.

Newspapers carried the story on front pages Thursday. Financial markets did not react sharply.