Embassies will be opened in East Jerusalem after members of the Organization of Islamic Cooperation (OIC) declared the city the capital of Palestine, Foreign Minister Mevlüt Çavuşoğlu said Thursday.

"Recognition of the Palestinian state is in line with U.N. decisions. We will strive for recognition of East Jerusalem as Palestine's capital," Çavuşoğlu said.

Çavuşoğlu added that the all kinds of efforts will be made until the U.S. retreats from its decision to recognize Jerusalem as the capital of Israel.

Following an extraordinary summit in Istanbul convened by President Recep Tayyip Erdoğan, the OIC declared East Jerusalem the capital of Palestine "under occupation" and urged the U.S. to withdraw from the peace process and back down from its Jerusalem decision.

Touching upon the topic of purchase of the S-400 air defense systems from Russia, Turkey's top diplomat said the agreement may be signed this week, adding that the technical work on setting up the S-400 systems would begin with Russia.

He also said Turkish engineers will be trained for deployment and handling of the Russian-made missile systems.

Turkey agreed to buy S-400 — Russia's most advanced long-range anti-aircraft missile system — in a more than $2 billion deal in September. The first system is expected to be delivered in 2019.