Turkey's President Recep Tayyip Erdogan, centre, flanked by Jordan's King Abdullah II, left and Palestinian President Mahmoud Abbas, right, poses with other leaders of Islamic nations prior to the opening session of the Organisation of Islamic Cooperation Extraordinary Summit in Istanbul. Picture: Lefteris Pitarakis/AP

Istanbul/Ramallah - A summit of Islamic nations declared East Jerusalem as the capital of the Palestinian state on Wednesday, in a counter move to the decision by US President Donald Trump to recognize Jerusalem as the capital of Israel.

Amid a day of fiery rhetoric at the 56-nation summit in Istanbul, Palestinian President Mahmoud Abbas said he will seek a UN General Assembly vote to nullify Israel's UN membership and demand full Palestinian membership in the UN Security Council.

"We will go to the UN General Assembly regarding Israel's membership because its membership is in violation of all international resolutions and we'll ask the Security Council for full membership in the General Assembly," Abbas said on Wednesday.

Read: EU rejects Trump's #Jerusalem move

Abbas and President Recep Tayyip Erdogan both said the US could no longer be regarded as a mediator. The Palestinian leader has requested UN sponsorship of an Israeli-Palestinian peace process.

Israel is "a country that feeds on blood and expands its borders by brutally killing children, civilians and women," said Erdogan.

"Hey Trump, are you standing behind this Israel? There's occupation here, there's torture here, there's terror here, are you defending that?" said the Turkish leader, who has been leading the charge against Trump's announcement this month, which included plans to move the US embassy to Jerusalem.

Also read: Trump, US face global condemnation after #Jerusalem decision

The OIC issued a statement saying it would "invite all countries to recognize the state of Palestine and East Jerusalem as its occupied capital."

In 2012, the UN General Assembly recognized the state of Palestine as a non-member observer state.

In Israel, Prime Minister Benjamin Netanyahu said he is "not impressed" by the Palestinian statements, in an apparent reference to Abbas' declarations.

"It is better for the Palestinians to recognize reality and act for peace, not for radicalization, and to recognize another fact about Jerusalem: not only is it the capital of Israel, we also maintain in Jerusalem freedom of worship for all religions," Netanyahu said at an event at the prime minister's office in Jerusalem.

Sources said more than two dozen leaders attended the summit and, in all, 56 nations were represented.

Read more: Netanyahu praises Trump's 'historic' #Jerusalem move

Abbas told the summit the US was no longer "qualified to mediate in the peace process" and demanded that a "new mechanism" headed by the UN be established to achieve a Palestinian state, with East Jerusalem as its capital.

"These unilateral steps by President Trump will not give any legitimacy to Israel in Jerusalem. It is a Palestinian Arab Muslim Christian city, the eternal capital of the state of Palestine," Abbas said.

Abbas' speech comes a week after Trump declared Jerusalem to be Israel's capital, upending decades of US policy towards the divided city and sparking a diplomatic firestorm.

The US has long been the main interlocutor for the Israeli-Palestinian peace process, most notably by brokering the Oslo Accords, signed in 1993, which paved the way for establishing Abbas' PA government.

"There can be no Palestinian state without the city of Jerusalem as its capital, and there will be no peace in the region and in the world without it," he added.

Other attendees at the summit included Jordanian King Abdullah II, Qatari leader Sheikh Tamim al-Thani and Iranian President Hassan Rowhani.

In Saudi Arabia, King Salman bin Abdulaziz, who did not attend the OIC meeting, described Trump's decision as a "flagrant bias against Palestinian people's historical and invariable rights" in Jerusalem.

He asserted the Palestinians' right to an independent state with East Jerusalem as its capital.

On Wednesday, small-scale clashes occurred throughout the West Bank and in the Gaza Strip with over a dozen injuries.

Palestinian youths have clashed with Israeli forces in recent days, leading to two deaths among protesters in Gaza. However, fears of widespread violence in the Palestinian Territories have not materialized.

Israel captured the eastern half of Jerusalem in the 1967 Six-Day War and later annexed the territory. Palestinians hope for East Jerusalem to be the capital of their future state.