Veterans Affairs (VA) Secretary David Shulkin has the White House's approval to root out agency staffers who oppose his policies and defy his leadership, he told Politico Tuesday night.

Shulkin's new chief of staff, Peter O'Rourke, is reportedly meeting with each VA staffer who is believed to have gone against Shulkin or pushed for his ouster.

"Those who crossed the line in the past are going to have to be accountable for those decisions," Shulkin told Politico.

He did not specify how many people were involved in what he called "subversive events," but multiple appointees have reportedly defied his orders and pushed for his ouster as head of the VA.

Shulkin, who also served in the VA under former President Obama, told The New York Times last week he was looking into identifying agency appointees who were "trying to undermine the department from within," and sought a meeting with chief of staff John Kelly to address his concerns.

A recent inspector general report found Shulkin improperly used taxpayer dollars during a trip to Europe. The report found that Shulkin spent most of the trip sightseeing, misused government resources by having the VA cover the cost of his wife's airfare and improperly accepted tickets to Wimbledon.

Shulkin has pushed back against the findings, but said that he has reimbursed the government for the cost of his wife's plane tickets and will pay for the Wimbledon tickets.

The White House indicated Tuesday that President Trump still has confidence in Shulkin despite the findings.