Donald Trump caused a diplomatic meltdown and security alerts on Wednesday after agreeing to move the U.S. Embassy from Tel Aviv to Jerusalem, thereby recognising the disputed holy city as the capital of Israel.

The U.S. president said the move was “long overdue” and that by “finally recognising the obvious, that Jerusalem is Israel’s capital” was “necessary for achieving peace,” despite both Israelis and Palestinians claiming the city as their capital.

Stressing “our lasting commitment” to a peace agreement, Trump said: “We are not taking a position of any final status issues, including the final boundaries or the resolution of contested borders. Those questions are up to the parties involved.”

The explosive move has been delayed by successive presidents since the U.S. Congress passed a law ordering it in 1995, but Trump made good on his campaign promise to follow-through this week, uniting the world in anger.

America’s allies and enemies all lined up to pour scorn on Trump, with criticism from the UK, France, Germany, Russia, China, Saudi Arabia, Egypt, Jordan, Turkey, the United Nations, the European Union and Pope Francis also expressing dismay.

In Israel and Jewish communities around the world, however, there was joy and relief, with many suggesting Trump had righted an historic wrong.

“It’s rare to be able to speak of new and genuine milestones in the glorious history of this city,” said Israeli Prime Minister Benjamin Netanyahu. “This is an historic day… It was here that our temples stood, our kings ruled and our prophets preached. Jerusalem has been the focus of our hopes, dreams and prayers for three millennia.”

American and Israeli flags are burned by protesters

Israeli President Reuven Rivlin also thanked Trump, saying: “There is no more fitting or beautiful gift as we approach 70 years since the State of Israel’s independence. Jerusalem is not, and never will be, an obstacle to peace for those who want peace.”

Jerusalem Mayor Nir Barkat said the relocation “sends a clear message to the entire world that the U.S. stands alongside the Jewish people and Israel”.

Israel considers both West and East Jerusalem to be its capital, so Trump’s embassy move is hugely symbolic and a boon to Jewish groups around the world, with Israel’s education minister Naftali Bennett saying Trump had “added another brick to the walls of Jerusalem, to the foundation of the Jewish nation”.

However, there was deepening concern this week that the announcement may precipitate a further round of violence, with Hamas chief Ismail Haniyeh saying: “Palestinians will not allow this to pass… Their options are open in defending their land and their sacred places.”

He was not alone in suggesting that Trump’s decision could end up costing lives, with Jordan’s King Abdullah II arguing that “ignoring Palestinian Muslim and Christian rights” in Jerusalem “could fuel terrorism”. Turkish President Recep Tayyip Erdogan added that it could prove “a red line” for the Muslim world.

Anticipating violence, both Germany and France immediately altered their travel advice for citizens travelling to Israel and the Palestinian territories, as the PLO’s chief negotiator Saeb Erekat said the move “pushes the region into the furnace of violence, chaos, extremism and bloodshed”.

Donald Trump at the Western Wall

The Arab world’s vehement protests are unlikely to worry Trump who, in his first year as president, appears to have thrived on antagonising the Muslim world, instigating a travel ban on Muslim countries and re-tweeting Islamophobic video content.

Palestinian Authority President Mahmoud Abbas said he would pull all Palestinian contacts with the U.S as a result, while Nabil Shaath, a senior Palestinian official, said any peace deal “dies here on the rocks”.

British Prime Minister Theresa May said in Parliament on Wednesday during Prime Minister’s Questions said the UK had no intention of following suit, while in Europe, the EU’s foreign policy chief Federica Mogherini joined French President Emmanuel Macron in piling on the opprobrium. Germany’s foreign minister added: “Anything that escalates the crisis during these times is counterproductive.”

And, in an extraordinary and highly unusual intervention, Pope Francis also waded in to make “a heartfelt appeal” to “respect the status quo,” adding: “I cannot remain silent about my deep concern for the situation… Jerusalem is a unique city, sacred to Jews. Christians and Muslims, where the holy places for the respective religions are venerated and it has a special vocation to peace.”