Washington (CNN) A government transparency group is suing the Interior Department, seeking records of any money spent on travel for the wife of Interior Secretary Ryan Zinke.

American Oversight claims Lola Zinke "has played an unusually prominent role" at the department, including joining her husband "extensively on his official travel."

The left-leaning group says Interior has not provided records it requested through the Freedom of Information Act four months ago. The group is demanding travel and other records for Lola Zinke, including "receipts for any expenditures made by the Department of Interior" for "travel, or any other expense."

It specifically asked about her presence on two of her husband's work trips: one to California in April and another to Alaska, Norway and Greenland in May with lawmakers.

The group said it wants to know "what role Secretary Zinke's wife is playing in running the department, how much it's costing taxpayers, and why she was jetting off to Europe with her husband on a military plane." The lawsuit was filed with the US District Court for the District of Columbia Circuit.

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