(CNN) A group of armed men stole a haul of gold and other precious metals worth at least $30 million from a Brazilian airport Thursday, according to Brazilian state news agency Agencia Brasil.

Eight men targeted a cargo terminal at Sao Paulo-Guarulhos International Airport, driving two trucks that resembled those driven by Brazilian federal police, the agency said. At the terminal, four men exited the truck wearing face coverings, Reuters reported, saying that at least one carried a rifle.

The armed men took two airport workers hostage, Reuters said. One was the airport's logistics supervisor, according to Agencia Brasil, which said the hostages were released unharmed.

The gunmen left the airport with approximately 750 kilograms (1,653 pounds) of gold and other metals due for shipment to Zurich and New York. No shots were fired and no one was injured during the robbery, the state news agency said.

According to Brazil's Federal Highway Police, the thieves may have had access to internal information about airport operations.

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