US President Joe Biden and Israel's Prime Minister Yair Lapid will sign a security "declaration" on Thursday affirming their united front against Iran, an American official said, as Biden holds bilateral talks in Jerusalem.

"This declaration is pretty significant and it includes a commitment to never allow Iran to acquire a nuclear weapon and to address Iran's destabilising activities, particularly threats to Israel," said a Biden administration official, who requested anonymity.

Biden touched down at Ben Gurion Airport near Tel Aviv on Wednesday for the first Middle East tour of his presidency, which will see him meet Israeli and Palestinian leaders before flying to Saudi Arabia.

Lapid, Israel's caretaker leader ahead of an election in November, had previously said Iran would top the agenda in his talks with the US president.

The declaration they sign would reaffirm "unbreakable bonds between our countries and expanding on the long standing security relationship between the United States and Israel", said the US official.

An Israeli official, also speaking on condition of anonymity, said the document was "going to be a living testimony to the unique quality, health, scope, depth and intimacy of the US-Israel relationship."

Israel is staunchly opposed to a nuclear deal Iran signed with world powers in 2015 and which Biden is trying to get back on track after his predecessor Donald Trump withdrew US support.

Biden said pulling out of the landmark accord was a "gigantic mistake".

Iran is "closer to a nuclear weapon now than they were before", the US president said in an interview aired Wednesday by Israel's Channel 12.

Asked whether the United States would use force to prevent Iran from acquiring nuclear weapons, Biden said: "If that was the last resort, yes."

- Saudi oil talks -
The president's meeting with Lapid will be followed by multilateral talks on investment with India and the United Arab Emirates, which will join remotely.

In addition to meeting with Israeli President Isaac Herzog, Biden will hold brief talks with Israeli opposition leader Benjamin Netanyahu.

The right-wing former prime minister is readying for another election campaign, with Israelis set to go to the polls for the fifth time in less than four years on November 1.

Biden is marking his tenth visit to Israel and is well-acquainted with Netanyahu.

Russia's invasion of Ukraine will remain a top priority for the Biden administration during his regional tour, with volatile oil prices due to be the focus of talks with Saudi officials.

The president will seek to persuade Saudi Arabia to pump more oil in order to drive down prices, which have fuelled US inflation to the highest levels in decades.

Israel has sought a delicate balance towards the Ukraine war, conscious of Russian forces in neighbouring Syria, its million citizens with ties to the former Soviet Union, and its firm US alliance.

Israeli officials have condemned the conflict in broad terms but the government has refused to send weapons to the Ukrainian army.

- No 'top down peace plan' -
The president on Wednesday renewed Washington's long-standing call for a two-state solution, but has not reversed Trump's controversial decision to recognise Jerusalem as Israel's capital.

Biden is due to meet Palestinian president Mahmud Abbas on Friday in Bethlehem, in the occupied West Bank, and pledge US financial support.

The US official that would include "a significant funding package" for hospitals that serve Palestinians in Israeli-annexed east Jerusalem, which Palestinians claim as their future capital.

Biden's administration will also announce measures towards providing 4G internet access in the West Bank and Israeli-blockaded Gaza strip, the US official said, addressing a long-standing Palestinian frustration.

But, with Israel in political limbo ahead of the November 1 election, Biden is not expected to push Lapid for significant policy changes regarding the Palestinians.

"We are not going to come in with a top down peace plan because we don't believe that would be the best approach," the US official said.

But, "if the two parties are prepared to talk, we will be there, and we will be there to help," the official added.