The White House has confirmed that President Donald Trump will formally recognise Jerusalem as Israel's capital tomorrow.
Breaking with decades of US policy, Mr Trump has already told leaders of the Palestinian Authority and Jordan that he plans to move the US Embassy from Tel Aviv to Jerusalem.
Senior White House officials say there will be two core components to the President's speech.
"First, the President will recognise — he will say that the United States Government recognises — that Jerusalem is the capital of Israel," officials said.
"He views this and we view this as a recognition of reality, both historic reality that Jerusalem has been the capital of the Jewish people, the Jewish faith, since ancient times, and modern reality that it has been the seat of government of all important — not all but nearly of the Israeli government — its government ministries, its legislature, its supreme court etc, in Israel since 1948."
The second component will be to direct the US State Department to begin the process of moving the US Embassy from its current site in Tel Aviv to a site in Jerusalem.
But that process may take years to complete.
"It is a practical impossibility to move the embassy tomorrow," the officials said.
"There are about 1,000 personnel in the embassy in Tel Aviv. There is no facility they can move into [in] Jerusalem as of today. It will take some time to find a site, address security concerns, design a new facility, fund a new facility — working with congress obviously — and build it.
"So this is not an instantaneous process."
The decision to move the US embassy breaks with policy that goes back almost to Israel's creation in 1948.
Under a law passed in 1995, every US president has signed a national security waiver every six months to keep the embassy in Tel Aviv and effectively postpone the decision to move the embassy to Jerusalem, for national security reasons.
The White House says Mr Trump will sign the waiver in order to avoid cuts to the State Department's funding, that the law requires as a result of the waiver.
"We are trying to set expectations and let people know this will be a matter of some years," the officials said.
"It won't be months. It won't be quick. It's going to take time to do all of these things I have outlined."
Decision a matter for the US, Julie Bishop says
The decision has sparked fears of a new wave of violence in the occupied Palestinian territories and across the Arab world.
Already protesters have burned posters bearing Donald Trump's face at the Church of Nativity in Bethlehem, in the West Bank, to voice their anger at the decision.
Jerusalem is home to key Muslim, Christian and Jewish shrines, which have long been a flashpoint in the protracted Israel-Palestinian conflict.
The United Nations, in its 1947 plan on partition, resolved to place Jerusalem under a "permanent international regime" administered by the UN, meaning neither side could claim the city as its capital.
However, Israel rejected that stance and passed legislation that declares Jerusalem is its "eternal and undivided capital".
Mr Trump first promised to move the US embassy to Jerusalem during last year's presidential election campaign.
The anticipated move has prompted security warnings from the US consulate to its personnel in Jerusalem.
World leaders, including from Turkey, Jordan and France, have urged Mr Trump not to make the move, because of the threat of violence in the region.
Foreign Minister Julie Bishop said the decision is a matter for the US.
"The Australian Government will continue our diplomatic representation to Israel from our embassy in Tel Aviv and our representation to the Palestinian Authority from our office in Ramallah," she said.
"Matters relating to Jerusalem are subject to final status negotiations between Israel and the Palestinian Authority.
"Australia supports a two-state solution where both peoples live within secure and internationally recognised borders."