Republican presidential front-runner Donald Trump said Monday he believes Israel should pay for defense aid it receives from the US, hours before he was slated to give a speech at the pro-Israel AIPAC policy conference.

During a press conference in Washington, Trump was asked whether he believed the Israeli government should pay for American defense, as he had called for other US allies such as South Korea, Japan and Saudi Arabia to do.

“I think Israel will do that also, yeah, I think Israel do—there are many countries that can pay and they can pay big league,” responded the billionaire businessman.

He spent most of his statement focused on the other countries, saying calling in debts would help “build wealth.”

Trump was scheduled to speak at the AIPAC policy conference in Washington later Monday. Some attendees have said they will protest his appearance by walking out.

Trump’s statement was an apparent break with a decades-old Washington policy to maintain a special security relationship with Israel, and came as Israel and the US are negotiating a new defense package said to be worth tens of billions of dollars over 10 years.

Israel currently receives $3.1 billion a year from Washington, most of which is required to be spent in the US.

Trump has said he is the most pro-Israel candidate on the campaign trail, but has also said he will be “neutral” in dealing with Israelis and Palestinians.