Israel is "keeping Hitler's spirit alive" according to Turkish prime minister and presidential hopeful Recep Tayyip Erdogan.

"What is the difference between what Nazis and Hitler did and what this Israeli administration is doing now?" the outspoken leader of moderate-Islamist AK Party said during a party meeting. "Israeli genocide is reminiscent of Hitler's holocaust because of acting with the same immorality as Hitler."

"Ottomans protected the Jewish people in the past. Don't you have any shame now? How immoral people are you?" he continued.

This is not the first time that Erdogan makes a controversial parallel between Israel and Nazi Germany. Earlier in July, he accused Israel of having "surpassed Hitler in barbarism".

Israel has advised its citizens against travelling to Turkey citing "the public mood" after attacks on Israeli embassies during protests in Istanbul and Ankara.

Erdogan is campaigning to be elected president in August election and has harshly criticised Israel's Operation Protective Edge, the military offensive against Palestinian Hamas militant group in the Gaza Strip that has killed more than 1,300 Palestinians, mainly civilians, and more than 50 Israelis, mainly soldiers.

Last week the New York-based lobby group American Jewish Congress slammed Erdogan for "inciting the Turkish population to violence against the Jewish people" and asked him to hand back an award that was granted to him for his Middle East peace efforts.

Erdogan said he would be "glad" to return the award.

"Take the award and stick it up your head," he said.

Turkey's ambassador to the US Serdar Kilic said Erdogan will continue criticising Israel's actions in Gaza.

"Attempts to depict Prime Minister Erdogan's legitimate criticisms of the Israeli government's attacks on civilians as expressions of anti-Semitism is an obvious distortion and an effort to cover up the historical wrongdoings of the Israeli government," Kilic said in a letter quoted by the Turkish news website Hurriyet.