The Organization of Islamic Cooperation (OIC) summit on Jerusalem will bring concrete results regarding U.S. President Donald Trump's recognition of the city as Israeli capital, senior adviser to Recep Tayyip Erdoğan Gülnur Aybet said Thursday.

Speaking to CNN International's Hala Gorani, Aybet reiterated President Erdoğan's warning that Jerusalem was the red line for Muslims.

"Turkey is holding the presidency of the OIC. Therefore, it is absolutely appropriate to issue a statement at the end of this meeting. I think you will see much more concrete results at the next week's meeting," Aybet said.

Aybet also said the U.S. likely lost its mediator role in the Palestinian-Israeli conflict.

"I don't think the U.S. will be able to play any kind of role in the peace process after this decision. Of course, everyone wants the peace process to resume and progress, but who will guarantee the U.S.' impartial mediating role?" she said.

Trump recognized the holy city of Jerusalem as Israel's capital Wednesday, prompting a universal diplomatic backlash amid fears of widespread tension in the Middle East.

America's leader appeared further isolated, as allies and foes alike denounced his decision and Palestinians questioned whether their right of statehood, as part of a peace deal brokered by Washington, was still possible.

Jerusalem remains at the core of the Israel-Palestine conflict, with Palestinians claiming East Jerusalem — occupied by Israel since 1967 — as the capital of a future Palestinian state.