Republican presidential front-runner Donald Trump told the New York Times he would consider stopping U.S. oil purchases from Saudi Arabia unless the Saudi government provide troops to fight Islamic State.

Trump's comment on Friday was included in a lengthy foreign policy interview published by the newspaper on Saturday and came in response to a question about whether, if elected president, he would halt oil purchases from U.S. allies unless they provided on-the-ground forces against Islamic State.

"The answer is, probably yes," Trump said, according to a transcript.

Trump has said the United States should be reimbursed by the countries it provides protection, even those with vast resources such as Saudi Arabia, a top oil exporter.

"And yet, without us, Saudi Arabia wouldn't exist for very long," Trump told the Times.

"... We're not being reimbursed for the kind of tremendous service that we're performing by protecting various countries. Now Saudi Arabia's one of them."

Trump also named in the interview retired Major General Gary Harrell, Major General Bert Mizusawa and retired Rear Admiral Charles Kubic as additional foreign policy advisors to the five named earlier this week who were criticized as obscure.

Trump has faced questions about his reluctance to reveal who was advising his campaign. He told the Times he was willing to rethink traditional U.S. alliances should he become president.

(Reporting By Amanda Becker; Editing by Bill Trott)