Leaders of the Muslim world's body called for an 'urgent' action against Israel for killing of Palestine's civilians last week.
Addressing the summit of the Organisation of Islamic Cooperation (OIC) that ended in Istanbul on late Friday, they also condemned the US administration for backing the Israeli government.
The OIC issued a final communique calling on the United Nations to launch an international investigation into the killings in Gaza, the creation of an international protection force for the Palestinians, and for the OIC to impose economic restrictions on any countries, companies or individuals who recognise Israel's annexation of Jerusalem.
Turkish president Recep Tayyip Erdogan called on Muslim leaders to unite and confront Israel, days after scores of Palestinians were killed by Israeli snipers as they marked 70 years of Israeli occupation, reports the Aljazeera television.
Speaking at the extraordinary OIC summit on Friday, Erdogan said Israel should be held accountable over the killings, which drew widespread international condemnation and triggered a wave of protests from Asia, through the Middle East to North Africa.
"To take action for Palestinians massacred by Israeli bandits is to show the whole world that humanity is not dead," Erdogan told the group of Muslim leaders gathered in Turkey's largest city, Istanbul.
The Turkish president described Israel's killing of Palestinians as "thuggery, atrocity and state terror." Several heads of state attended the Istanbul summit, but Saudi Arabia, the host of the 57-member OIC, sent only a senior foreign ministry official. Bahrain, Egypt and the UAE also sent lower-level ministers.
Speaking at the conference, Qatar's Emir SheikhTamim bin Hamad Al Thani said the Palestinian cause had "become a symbol for oppressed people everywhere" and condemned Israel for the "brutal massacre" of peaceful demonstrators.
"Who among us does not know the declared siege forced on the Gaza Strip and the collective punishment against its population?" the emir said.
"The Gaza Strip has been transformed into a large concentration camp for millions of people who are deprived of their most basic rights to travel, education, work and medical treatment.
"When their sons take arms they are called terrorists, and when they stage peaceful demonstrations, they are called extremists, and are shot dead with live ammunition."
For his part, Palestinian Prime Minister Rami Hamdallah said the US had become "part of the problem and not the solution" and called the relocation of the embassy "an act of aggression against the Islamic nation, against Muslims and Christians".
Jordan's King Abdullah II urged the adoption of urgent measures to back "the resistance of Palestinians", while Iranian President Hassan Rouhani called for economic and political measures against the US and Israel.
Foreign Minister Abul Hassan Mahmood Ali is leading an eight-member Bangladesh delegation to the 7th extraordinary summit.
Mr Ali participated in the summit as the chair of the 45th Council of Foreign Minister, the Foreign Office said in a statement.
The Bangladesh delegation includes Prime Minister's security affairs adviser Tarique Ahmed Siddique, Bangladesh PR to OIC Ambassador Golam Moshi, Bangladesh Ambassador to Turkey M Allama Siddiki and senior officials of the ministry and Bangladesh missions.
"The OIC must find an alternative, multi-power, multi-stake-holder platform to push and take forward the peace process to a meaningful end," foreign minister AH Mahmood Ali told the summit.
"We must engage the international community proactively, with immediate action by the Ministerial Group on Al Quds to reach out to important state capitals as well as with activation of OIC ambassadors in New York, Geneva, The Hague and Brussels," he added.
Mr Ali said the impunity demonstrated by Israel and the disregard shown by the US administration to international norm and laws have "outraged the people of Bangladesh".