US President Donald Trump, seen here visiting the Western Wall, has pledged he will recognize Jerusalem as Israel's capital

Washington (AFP) - President Donald Trump on Tuesday slapped down warnings of widespread Middle East unrest as he told anxious Arab leaders he still intends to move the US embassy to Jerusalem, on the eve of a much-anticipated policy speech.

Amid a frantic round of telephone diplomacy, Trump told Palestinian leader Mahmud Abbas and Jordan’s King Abdullah that the deeply controversial move was coming, but crucially did not give a timeframe.

Trump “informed the president (Abbas) on his intention to move the US embassy from Tel Aviv to Jerusalem,” the Palestinian leader’s office said in a statement that was echoed from Amman.

Trump missed a Monday deadline to decide whether to keep the embassy in Tel Aviv or fulfill a campaign promise and move it to Jerusalem – de facto recognizing Israel’s claim on the disputed city.

Such a move would delight both Trump’s donors and the conservative and evangelical base that is so vital for the embattled president’s survival.

But it could also extinguish Trump’s much-vaunted efforts to broker Middle East peace and ignite the flames of conflict in a region already reeling from crises in Lebanon, Syria, Iraq, Yemen and Qatar.

The 71-year-old president will give a speech on his decision Wednesday, White House press secretary Sarah Sanders said.

Anticipating widespread demonstrations, US government officials have already been ordered to avoid Jerusalem’s Old City and the West Bank.

- ‘Threading the needle’? -

US officials talk of “threading the needle” – fulfilling Trump’s pledge, while keeping the peace process on the rails – but critics say Trump’s approach is more like “splitting the baby.”

Officials say he will hold off on moving the embassy right away, largely for logistical reasons, but may present a timetable for that to go ahead on Wednesday.

Equally controversially, he is also expected to recognize Jerusalem as Israel’s capital, while leaving open questions about control of the predominantly Palestinian eastern part of the city.

The White House argues that such a move would not prejudge final talks and would represent the reality that west Jerusalem is and will continue to be part of Israel under any settlement.

All foreign embassies in Israel, including that of the United States, are currently located in Tel Aviv although most countries have consular representation in Jerusalem

But it could upend a decades-old western policy – observed by both Republican and Democratic presidents – that stated Jerusalem’s status can only be decided by negotiation.

Saudi Arabia’s King Salman warned his close ally that moving the US embassy was a “dangerous step” that could rile Muslims around the world.

“Mr Trump! Jerusalem is a red line for Muslims,” Turkey’s President Recep Tayyip Erdogan said in a raucous televised speech, echoing alarm expressed by Palestinian and Arab leaders.

In his address, Erdogan warned that any move to back Israel’s claim to the city would mobilize “the entire Islamic world” and even prompt Ankara to sever its recently renewed diplomatic ties with the Jewish state.

Israel’s government has largely been silent. It earlier left the Trump administration with the impression that moving the embassy was a “no go,” leading to Trump signing the waiver the first time around.

The armed Islamist Hamas movement has threatened to launch a new “intifada” or uprising.

Most of the international community, including the United States, does not formally recognize Jerusalem as Israel’s capital.

- ‘A way must be found’ -

Jerusalem is home to sites that are holy to Jews, Muslims and Christians

Following talks in Brussels with US Secretary of State Rex Tillerson, top EU diplomat Federica Mogherini warned that any move which risked undermining efforts to jumpstart moribund peace talks “must absolutely be avoided.”

“A way must be found through negotiations to resolve the status of Jerusalem as the future capital of both states, so that the aspiration of both parties can be fulfilled,” she said.

In Cairo, Arab League chief Ahmed Abul Gheit warned it would be viewed as an act of “clear aggression” against the Arab and Muslim world.

The Palestinians said it would shatter any illusion about Trump’s ability to fairly mediate in any talks.

“That totally destroys any chance that he will play a role as an honest broker,” said Nabil Shaath, an adviser to Abbas.

- The Jerusalem Embassy Act -

In Israel, however, hardline Defense Minister Avigdor Lieberman hailed the moment as a “historic opportunity” for Trump, expressing hope he would see the US embassy in Jerusalem “next week or next month.”

Israel seized the largely-Arab eastern sector of Jerusalem during the Six-Day War, claiming the entire city as its "eternal and undivided capital," but the Palestinians want the eastern sector as capital of a Palestinian state

The US Congress has already made its aim clear in the so-called Jerusalem Embassy Act, which was passed in 1995 and which stated that the city “should be recognized as the capital of the State of Israel” and that the US embassy should be moved there.

But an inbuilt waiver, which allows the president to temporarily postpone the move on grounds of “national security,” has been repeatedly invoked by successive US presidents, meaning the law has never taken effect.

Israel seized the largely-Arab eastern sector of Jerusalem during the 1967 Six-Day War and later annexed it, claiming both sides of the city as its “eternal and undivided capital.”

But the Palestinians want the eastern sector as the capital of their future state and fiercely oppose any Israeli attempt to extend sovereignty there.

Several peace plans have unravelled over the issue of how to divide sovereignty or oversee sites in the city that are holy for Christians, Jews and Muslims.

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