The Organisation of Islamic Cooperation (OIC) has rejected the United States' decision to recognise Jerusalem as the capital of Israel. <br/><br/>Speaking today at the opening of an extraordinary OIC summit in Istanbul, the group's secretary general, Yousef al-Othaimeen, urged Muslim leaders to work together to present a united response to the move. <br/><br/>He said the OIC rejects and condemns the American decision which is a violation of international law and it will create a situation of instability in the region and in the world. Speaking at the summit, Turkish President Recep Tayyip Erdogan has urged leaders of Muslim nations to recognise Jerusalem as the "occupied capital of the Palestinian state". <br/><br/>Erdogan said the US decision to recognise the city as Israel's capital was "null and void". Mr Erdogan also again accused Israel of being a "state of terror". Palestinian President Mahmood Abbas, in his address, called the decision of US President Donald Trump a flagrant violation of international law. <br/><br/>According to the Palestinian President, the decision of Trump could be used by extremists to turn a political struggle into a religious one. <br/><br/>Abbas warned that there could be no peace or stability in West Asia until Jerusalem is recognised as the capital of a Palestinian state. Leaders of the Muslim world are attending the OIC summit, looking to rally for a coordinated response to the US move on Jerusalem.