Opposition is growing in the Arab and wider Muslim world as Donald Trump is expected to announce US recognition of Jerusalem as Israel's capital.
Reports say the president will make the statement this week but will further delay acting on a campaign pledge to move the US embassy to the city.
The head of the Arab League, Turkey, Jordan and the Palestinian leader have warned of consequences of the move.
The city's fate is one of the thorniest issues between Israel and the Arabs.
The Israeli government has not publicly commented on the anticipated announcement by Mr Trump.
A deadline for Donald Trump to sign a waiver delaying the relocation of the US embassy from Tel Aviv to Jerusalem expires on Monday.
Every president, including Mr Trump, has signed the waiver every six months since US Congress passed an act in 1995 calling for the embassy to be moved.
Mr Trump repeatedly pledged during his election campaign to move the embassy, and while he has said it was still his intention, he has not yet done so.
There are signs however he will make a statement on Wednesday announcing Washington's recognition of Jerusalem as the capital of Israel while holding off moving the embassy.
What's so contentious about the move?
The status of Jerusalem goes to the heart of Israel's conflict with the Palestinians, who are backed by the rest of the Arab and wider Islamic world.
The city is home to key religious sites sacred to Judaism, Islam and Christianity, especially in East Jerusalem.
Israel occupied the area in the 1967 Middle East war and regards the entire city as its indivisible capital. The Palestinians claim East Jerusalem as the capital of a future state, and according to 1993 Israel-Palestinian peace accords, its final status is meant to be discussed in the latter stages of peace talks.
Israeli sovereignty over Jerusalem has never been recognised internationally, and all countries, including Israel's closest ally the US, maintain their embassies in Tel Aviv, Israel's commercial capital.
Since 1967, Israel has built a dozen settlements, home to about 200,000 Jews, in East Jerusalem. These are considered illegal under international law, though Israel disputes this.
If the US recognises Jerusalem as Israel's capital, it will put it out-of-step with the rest of the international community and reinforce Israel's position that settlements in the east are valid Israeli communities.
It would also raise a question over how the US will treat resolutions dealing with East Jerusalem at the UN. The US has a power of veto and could use this to block future motions critical of Israeli policy in the east.
What has been the international reaction?
There is growing anger towards Washington among its allies in the Middle East.
Jordan, the custodian of Islamic holy sites in Jerusalem, has warned of "grave consequences" if Donald Trump goes ahead, and has called for an emergency meeting of key regional and Islamic blocs the Arab League and the Organization of the Islamic Conference to discuss the issue.
Arab League chief Abul Gheit warned such a move would "nourish fanaticism and violence".
Turkish Deputy Prime Minister Bekir Bozdag described it as a "major catastrophe" which would "completely destroy the fragile peace process" and lead to new conflicts.
Palestinian President Mahmoud Abbas has contacted world leaders urging them to intervene, saying "such a US decision would destroy the peace process and drag the region into further instability".
The US has brokered decades of on-off peace talks, and the Trump administration is formulating fresh peace proposals - but recognising Jerusalem as Israel's capital would compromise Washington's neutrality in the eyes of the Palestinians.
Will Donald Trump definitely make the announcement?
It remains uncertain though whether the president will recognise Israeli sovereignty over Jerusalem.
The White House has neither confirmed nor denied his intention, and in a rare public speech on Sunday his son-in-law and adviser Jared Kushner refused to be drawn on the issue.
"The president is going to make his decision and he's still looking at a lot of different facts," he told the Saban Forum in Washington.
"When he makes his decision he'll be the one to want to tell you, not me," he said.