Various world leaders have expressed 'strong concerns' at the move
The US President Donald Trump has officially recognised Jerusalem as the capital city of Israel.
In a speech at the White House he said the move was long overdue and claimed it was a "necessary condition" for achieving peace.
He also confirmed the US embassy in the country would be moved to the city – but did not give any timeline for when that might happen.
The Tánaiste and Minister for Foreign Affairs Minister Simon Coveney was this afternoon among a host of world leaders to warn President Trump against the move, noting that it would make progress in Middle East Peace Process more difficult and provoke tension across the region.
The move backs Israel’s claim over the entire city and ends decades of US policy stipulating that the city's status must be decided in negotiations with the Palestinians.
Israel considers the whole of the city as its "eternal, undivided capital" - but East Jerusalem is considered illegally occupied under international law.
Palestinians view the Eastern part of the city as their own capital.
The city is home to sites that are holy to Muslims, Jews and Christians.
In his speech, President Trump said the US would support a two-state solution - if approved by both the Israelis and the Palestinians - and called for calm and tolerance in the wake of the decision.
“I have judged this course of action to be in the best interest of the United States of America and the pursuit of peace between Israel and the Palestinians,” he said.
“This is a long overdue step to advance the peace process and to work towards a lasting agreement.
“Israel is a sovereign nation with the right, like every other sovereign nation, to determine its own capital.
“Acknowledging this as a fact is a necessary condition for achieving peace.”
He made no mention of the Palestinian claim – but suggested Israel’s boundaries in the city are still to be determined.
He said Israel has made Jerusalem its capital since US President Harry S. Truman recognised the State.
“Today Jerusalem is the seat of the modern Israeli Government,” he said.
“It is the home of the Israeli Parliament, the Knessa as well as the Israeli Supreme Court.
“It is the location of the official residence of the Prime Minister and the President.
“It is the headquarters of many Government ministries.”
The move has been condemned by leaders across the world with Turkey labelling it “irresponsible” and the French President Emmanuel Macron warning the status of Jerusalem must be determined through negotiations between Israel and Palestine.
Around 1,000 staff members will need to be re-located, with US Congress assisting the State Department to find a new site, before a new building is designed and constructed.
Security is high on the White House agenda when sourcing a new spot for the embassy.
US officials have claimed the recognition of Jerusalem as Israel's capital is an acknowledgement of "historical and current reality," rather than a political statement.
In a phone call yesterday, the Palestinian President Mahmoud Abbas "warned of the dangerous consequences of such a decision on the peace process, security and stability in the region and the world."
World leaders have warned such a move would inflame tensions in the region – and Mr Abbas has previously warned the Trump administrationthat it would kill off the peace process and strip the US of its role as honest broker.
Egypt's President Abdel Fattah el-Sisi has also spoken to Mr Trump about the plan and told him there was no need to "complicate" matters in the region, a statement from the Cairo government said.
France's President Emmanuel Macron also called Mr Trump and reminded him the future of Jerusalem should be determined in negotiations on setting up a Palestinian state.
"Recognising Jerusalem as the capital of Israel does not calm a conflict, rather it fuels it even more," Germany's foreign minister, Sigmar Gabriel, told reporters at NATO HQ in Brussels.
Foreign Affairs Minister Simon Coveney has said Ireland "shares concerns" of France's President Emmanuel Macron on this issue.
He later said the decision would "provoke tension across the region", adding that he had been in contact with the US Embassy to express "strong concerns" over the issue.
I contacted US Embassy directly yesterday to express Irelands strong concerns and to urge USA not to recognise Jerusalem as Israel's capital this week - it will make progress in Middle East Peace Process more difficult and provoke tension across the region https://t.co/7RWlM01pzA— Simon Coveney (@simoncoveney) December 6, 2017
President Macron has warned Mr Trump the move was a bad idea.
In a phone call with the US president, Mr Macron "expressed his concern with the possibility that the United States might unilaterally recognise Jerusalem as capital of the state of Israel", according to a statement issued by the French government.
The statement said Mr Macron "reaffirmed that the status of Jerusalem must be resolved through peace negotiations between Israelis and Palestinians, and particularly those relating to the establishment of two states, Israel and Palestine, living side by side in peace and security with Jerusalem as their capital."
Responding to the reports, Pope Francis called for the "status quo" to be respected,
"I cannot silence my deep concern over the situation that has emerged in recent days," the Pope said. "I appeal strongly for all to respect the city's status quo, in accordance with the relevant UN resolutions."
Political factions led by Mr Abbas's Fatah movement have called for daily protest marches.
The US has responded by ordering government employees to avoid Jerusalem's Old City and the West Bank.
US officials added that an announcement on the embassy's relocation would probably not happen for around six months, but planning would begin straight away.
Israel claims the city has been the capital of the Jewish people for 3,000 years and the country's capital for 70 years.
The country captured East Jerusalem in 1967 and annexed it - but that move was not recognised internationally.
Last year, the UN Security Council reaffirmed that Israel’s establishment of settlements in Palestinian territory occupied since 1967 was a “flagrant violation under international law and a major obstacle to the vision of two States living side-by-side in peace and security, within internationally recognized borders.”