The Turkish government's spokesman on Wednesday said that the United States' decision to recognize Jerusalem as the capital of Israel will plunge the region and the world into "a fire with no end in sight".
"Declaring Jerusalem a capital is disregarding history and the truths in the region, it is a big injustice/cruelty, shortsightedness, foolishness/madness, it is plunging the region and the world into a fire with no end in sight," Deputy Prime Minister Bekir Bozdag said on Twitter.
"I call on everyone to act logically, respect the agreements they signed and behave reasonably, avoid risking world peace for domestic politics or other reasons," he said.
Britain is concerned about Trump's plan to recognize Jerusalem as Israel's capital, foreign minister Boris Johnson said.
"We view the reports that we have heard with concern, because we think that Jerusalem obviously should be part of the final settlement between the Israelis and the Palestinians, a negotiated settlement," Johnson said as he arrived for a NATO meeting in Brussels.
Pope Francis Wednesday defended the "status quo" in Jerusalem.
"I cannot silence my deep concern over the situation that has emerged in recent days. At the same time, I appeal strongly for all to respect the city's status quo, in accordance with the relevant UN resolutions," the pope said in his weekly address.
The UN envoy for the Middle East peace process said Wednesday that Jerusalem's future status must be negotiated between Israelis and Palestinians and warned of the repercussions of any action over the disputed city.
"The (UN) secretary general has spoken many times on this issue... and he has said that we all have to be very careful with the actions we take because of the repercussions of these actions," Nickolay Mladenov told a conference ahead of US President Donald Trump's plan to recognize Jerusalem as Israel's capital.
"The future of Jerusalem is something that needs to be negotiated with Israel, with the Palestinians, sitting side by side directly in negotiations."
Germany is concerned that violent clashes could erupt in the Middle East, the Foreign Ministry said on Wednesday.
In an update of its travel advice for Israel and the Palestinian territories, the Foreign Ministry in Berlin said:
"From December 6, 2017, there may be demonstrations in Jerusalem, the West Bank and the Gaza Strip. Violent clashes can not be ruled out."
China warned on Wednesday that Trump's plan to recognize Jerusalem as Israel's capital could fuel tensions in the region.
"We are concerned about the possible escalation of tensions," foreign ministry spokesman Geng Shuang told a regular news briefing.
"All relevant parties should bear regional peace and tranquility in mind, be cautious in words and deeds, avoid impacting the foundation for the settlement of the issue of Palestine, and avoid causing new confrontation in the region."
A senior administration official said Trump would make the announcement -- ignoring frantic warnings from US allies in the region and around the world -- at 1800 GMT from the White House.
Moving the embassy and recognizing Jerusalem as Israel's capital would mark a major shift in US policy that would upturn decades of precedent and run contrary to international consensus.
Israel occupied east Jerusalem and the West Bank in the Six-Day War of 1967. It later annexed east Jerusalem in a move never recognized by the international community.
Israel claims the entire city as its indivisible capital, while the Palestinians want the eastern sector as the capital of their future state.
The city's status is among the most difficult issues in the conflict. Traditional US policy has been that it must be negotiated between the two parties.