Republican presidential front-runner Donald Trump told the New York Times he would consider stopping US oil purchases from Saudi Arabia unless the Saudi government provides 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 US 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. – Reuters