President Donald Trump will recognise Jerusalem as Israel’s capital on Wednesday despite intense Arab, Muslim and European opposition to a move that would upend decades of the U.S. policy and risk potentially violent protests.

Mr. Trump will instruct the State Department to begin the multi-year process of moving the American embassy from Tel Aviv to the holy city, U.S. officials said on Tuesday. It remains unclear, however, when he might take that physical step, which is required by law but has been waived on national security grounds for more than two decades.

The officials said numerous logistical and security details, as well as site determination and construction, will need to be finalised first. Because of those issues, the embassy is not likely to move for at least three or four years, presuming there is no future change in U.S. policy.

To that end, the officials said Mr. Trump will sign a waiver delaying the embassy move, which is required by the law every six months. He will continue to sign the waiver until preparations for the embassy move are complete.

The officials said recognition of Jerusalem as Israel’s capital will be an acknowledgement of “historical and current reality” rather than a political statement. The city’s physical and political borders would not be compromised. They noted that almost all of Israel’s government agencies and parliament are in Jerusalem, rather than Tel Aviv, where the U.S. and other countries maintain embassies.

The declaration is a rhetorical volley that could have its own dangerous consequences. The U.S. had never endorsed the Jewish state’s claim of sovereignty over any part of Jerusalem and had insisted its status be resolved through Israeli-Palestinian negotiation.

The concerns are real, as Mr. Trump’s decision could be viewed as the country discarding its longstanding neutrality and siding with Israel at a time that President’s son-in-law Jared Kushner has been trying to midwife a new peace process into existence. Mr. Trump, too, has spoken of his desire for a “deal of the century” that would end Israeli-Palestinian conflict.

Jerusalem includes the holiest ground in Judaism. But it’s also home to Islam’s third-holiest shrine and major Christian sites, and forms the combustible center of the Israeli-Arab conflict. Any perceived harm to Muslim claims to the city has triggered volatile protests in the past, both in the Holy Land and across the Muslim world.

Within the Trump administration, officials on Tuesday fielded a flood of warnings from allied governments.