Cairo's Al-Azhar warns Trump's Jerusalem embassy move will 'open the floodgates of hell'

The Grand Imam of al-Azhar - the highest seat of learning in the Sunni Muslim world - has said US plans to relocate its Israeli embassy to Jerusalem will "open the floodgates of hell to the West".

Ahmed al-Tayeb made the comments on Tuesday during a meeting with former UK prime minister Tony Blair, according to a statement from the Cairo-based institution.

"If the door is opened for foreign embassies to move to Jerusalem, the floodgates of hell will be opened to the West more so than to the East," he said.

The Grand Imam said the potential move to officially recognise the holy city as Israel's capital would "fuel anger among all Muslims and threaten world peace".

US 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.

The 71-year-old president will give a speech on his decision on 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.

Jerusalem remains at the core of the perennial Israel-Palestine conflict, as Palestinians want Israeli-occupied East Jerusalem as the capital of a future state.

Israel regards Jerusalem as its capital, a position nearly the entire world rejects saying its status should be determined in peace talks with the Palestinians.

The international community considers east Jerusalem illegally occupied by Israel and most countries have their embassies in the coastal city of Tel Aviv.

Trump's potential move has been condemned by leaders across the Middle East.