US Interior Dept. watchdog launches investigation into Zinke's travel
U.S. Interior Secretary Ryan Zinke rides a boat to Georges Island, while traveling for his National Monuments Review process, in Boston Harbor, Massachusetts, U.S., June 16, 2017. REUTERS/Brian Snyder

The Interior Department's watchdog agency has launched an investigation into Secretary Ryan Zinke's travels after reports emerged last week that he had used a private plane owned by an oil executive, the inspector general's office said on Monday.

The Inspector General (IG) opened an investigation on Friday after receiving numerous complaints on Thursday about Zinke's travels, including the use of three chartered flights, IG spokeswoman Nancy DiPaolo told Reuters.

One of those flights taken in June from Las Vegas to near his hometown in Montana was on a plane owned by oil and gas executives, costing taxpayers over $12,000, the Washington Post reported last week.

Zinke denied any inappropriate travel in a speech at conservative think tank the Heritage Foundation on Friday and said his travels were approved by "career employees" of the Interior Department's ethics office.

Last week U.S. Health and Human Services Secretary Tom Price resigned under pressure from President Donald Trump amid an uproar over Price's use of costly private charter planes for government business.

(Reporting by Valerie Volcovici; Editing by Sandra Maler)