President Donald Trump landed in Israel on a groundbreaking direct flight Monday from Saudi Arabia and expanded a core theme of his Sunday speech in Riyadh: the U.S. will stand with Arab nations and Israel against the threats they all agree are posed by Iran.

Meeting with President Reuven Rivlin in Jerusalem, Trump stressed that Iran's support of violent groups in the region also presented an opportunity for Israel to come closer to countries in the Gulf, some of which don't have diplomatic relations with Israel. There's a "growing realization among your Arab neighbors that they have common cause with you in the threat posed by Iran," Trump told Rivlin.

"The United States and Israel can declare with one voice that Iran must never be allowed to develop nuclear weapons," Trump said. "Never, ever. And must cease its deadly funding, training and equipping of terrorists and militias."