U.S. decision to recognize Jerusalem as Israel's capital is extremely alarming, Presidential Spokesperson İbrahim Kalın said Tuesday, noting that the decision contradicts international agreements and U.N. resolutions.

In a series of messages he posted on his official Twitter account, Kalın said that the decision is also against Jerusalem's historical and religious status.

Kalın highlighted that such a step would completely destroy the already fragile peace process in the Middle East and create new tensions and conflict.

"We hope that the U.S. administration does not make this calamitous mistake" Kalın said, adding that the protection of Jerusalem and the Haram al-Sharif (Noble Sanctuary), also known as the Temple Mount, is critical.

The leader of Turkey's main opposition Republican People's Party (CHP) on Tuesday also criticized the possible U.S. move.

"Jerusalem is the keystone of the Middle East," Kemal Kılıçdaroğlu told a rally in the capital Ankara marking Women's Rights Day.

"If they [the U.S] make a wrong decision on Jerusalem, it will lead to more blood and tears in the Middle East," he added.

Kılıçdaroğlu also voiced his support for Turkey's "Palestinian brothers". "No one can prevent our support for them," he said.

Earlier today, Turkish President Recep Tayyip Erdoğan called the status of Jerusalem a "red line" for Muslims.

As part of his election campaign, U.S. President Donald Trump pledged to relocate the country's embassy in Israel from Tel Aviv to Jerusalem. The recent move has been opposed by a number of world powers, including Turkey and the Arab League.

While Israel considers Jerusalem as its capital, the world opposes this, saying that the city's status should be determined in peace talks with Palestinians, who consider the eastern part of the city as their future capital.