Republican and Democratic presidential front-runners Donald Trump and Hillary Clinton are both to address the annual policy conference of the American Israel Public Affairs Committee (AIPAC), the main pro-Israel organization in the US, in Washington next week.

They are expected to expose their views on Israel and Middle East policy.

According to CNN, Trump and Clinton have rarely spoken to the same audiences so far in the campaign. But each candidate has tried to position themselves as a pro-Israel voice in their respective parties.

Trump's address will be watched particularly closely. Rivals have started targeting him for comments he made about pledging to be "neutral" in the Israeli-Palestinian conflict, with Republicans saying that it suggests Trump is not sufficiently pro-Israel.

"There's nobody on this stage that's more pro-Israel than I am," he said during a recent CNN's Republican debate. He called the peace process "the toughest deal, the toughest negotiation there probably is of any kind, no matter where you look, no matter how hard you look. But I would like to give it a shot."

Earlier, Trump canceled his presence at the upcoming Republican presidential debate in Salt Lake City in order to address the AIPAC conference.

"I'm making a very major speech in front of a very important group of people," Trump said, adding that the remarks will be delivered before the American Israel Public Affairs Committee. Trump said his speech at the group's conference in Washington "was scheduled a while ago."

Trump’s main rival in the Republican presidential nomination, Ted Cruz is also expected to address the AIPAC conference.