At the same time, the Vatican consistently has called for a special status for Jerusalem, particularly its Old City, in order to protect and guarantee access to the holy sites of Judaism, Christianity and Islam.
The pope told thousands of people at his general audience: "I can not keep quiet about my deep worry about the situation that has been created in the last few days".
Speaking before Trump's announcement, Pope Francis defended the "status quo" of Jerusalem.
The Pope said he "cannot keep silent" over the "situation that has arisen in recent days", and called for respect for the "status quo of the city, in accordance with the relevant resolutions of the United Nations".
TheNewsGuru.com reports that the US President had on Wednesday declared that United States will henceforth deal with Jerusalem as the capital of Israel and directed the US Embassy in the country be moved Tel Aviv to Jerusalem.More news: Jessica Chastain's Villain Looks Fierce in 'Dark Phoenix' First Look
Trump's decision has been strongly condemned by USA allies and rivals alike.
Jerusalem remains at the core of the Israel-Palestine conflict, with Palestinians hoping that East Jerusalem - now occupied by Israel - might eventually serve as the capital of a future Palestinian state.
The Pope made his comments on Wednesday during a previously scheduled meeting with a Palestinian delegation of religious and intellectual leaders.
Although the embassy move will take several years, Trump has directed the US State Department to "start the process".
"At the end of his weekly general audience, attended by thousands of people, the Pope called for the status quo on Jerusalem to be preserved, saying that he was very anxious because the American decision could "[add] new elements of tension to a global panorama" that is already marred "by so many and cruel conflicts".More news: Roger Goodell finally signs contract extension with NFL
Mr Abbas is also understood to have called Pope Francis to express his concerns about the move.
British Prime Minister Theresa May said Jerusalem "should ultimately form a shared capital between the Israeli and Palestinian states".
He added that Israel must not allow its own interests to "disrupt what the United Nations has repeated many times, and what has also been the logical and coherent position of the Holy See for all the past decades".
Arab leaders have warned the Trump administration's decision would subvert decades of USA foreign policy and risk triggering further conflicts and violence in the Middle East.More news: Watch list (ROI - a financial ratio): Kinder Morgan, Inc. (NYSE:KMI)