“Palestine is an innocent victim. As for Israel, it is a terrorist state, yes, terrorist!” Erdogan said in a fiery speech in the central city of Sivas. “We will not abandon Jerusalem to the mercy of a country that kills children.”
Erdogan further said that decisions made at the approaching meeting of the Organization of Islamic Cooperation (OIC) would show that US recognition of Jerusalem as the Israeli capital would not be easy to implement.
A spokesman for Erdogan on Wednesday had announced that the OIC would a hold an urgent meeting in Turkey on December 13 to coordinate a response to the decision by the United States.
The OIC, established in 1969, consists of 57 member states with a Muslim majority or a large Muslim population.
"We explained to all our interlocutors that the United States' decision does not comply with international law, diplomacy or humanity," Erdogan said at a Justice and Development Party (AKP) assembly in Sivas, referring to phone calls he made to leaders including French President Emmanuel Macron and the Pope.
"With the roadmap we will create during the OIC meeting, we will show that the decision will not be easy to implement," he said, adding that Turkey considered US President Trump's Jerusalem announcement void.
The Arab League, in a statement issued after an emergency session in Cairo on Saturday, called the announcement a "dangerous violation of international law" and said it would seek a UN Security Council resolution rejecting the US move.
The Arab League, which consists of Arabic-speaking nations, currently has 22 active member states.
Trump's announcement has also upset US allies in the West. At the United Nations, France, Italy, Germany, Britain and Sweden called on the United States to "bring forward detailed proposals for an Israeli-Palestinian settlement".
Palestinians took to the streets after the US announcement. Demonstrations also took place in Iran, Jordan, Lebanon, Tunisia, Somalia, Yemen, Malaysia and Indonesia, as well as outside the US Embassy in Berlin.
AFP and Reuters contributed to this report.