(CNN) The Department of the Interior's inspector general's office opened an investigation Friday morning into Secretary Ryan's Zinke's travel.

Queries into Zinke's travel come just days after former Health and Human Services Secretary Tom Price resigned after criticism of his travel. Reports showed Price had traveled multiple times via taxpayer-funded private charter planes.

Zinke took three charter flights, including one from Las Vegas to his home state of Montana and another in the US Virgin Islands.

The three instances where he used non-commercial and non-military aircraft for travel included a bipartisan congressional delegation led by the Senate and natural resources committee to the Arctic Circle, Zinke said

The second instance, he said, was flying "late at night to the great state of Montana on invitation to meet the great governor of the great state of Montana."

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