Israeli Prime Minister Benjamin Netanyahu is "a cold-blooded killer of modern times," Turkish Foreign Minister Mevlut Cavusoglu said during a bitter exchange on social media.
Netanyahu is "responsible for massacres of thousands of innocent Palestinians," Cavusoglu wrote on Twitter, in response to a tweet by the prime minister a day before.
Netanyahu had lashed out on Saturday at Turkish President Recep Tayyip Erdogan, calling him "the occupier of northern Cyprus, whose army massacres women and children in Kurdish villages, inside and outside Turkey." 
Erdogan "should not preach to Israel," he continued on Twitter.
The back-and-forth erupted after Erdogan addressed a youth event on Saturday in Istanbul.
"Do not kick the enemy you have brought down to the ground. You are not a Jew in Israel," Erdogan told the crowd, according to state news agency Anadolu.
Relations between Turkey and Israel have soured over a number of recent issues, including a law passed in July that declared Israel as the exclusive homeland of the Jewish people.
Erdogan back then condemned Israel as the most racist country in the world, saying "the spirit of Hitler has been resurrected in some Israeli authorities."
In May, the Israeli ambassador to Turkey returned to Israel over the killings of dozens of Palestinian protesters angered by the opening of the new US embassy in the contested city of Jerusalem.
Also on Twitter on Sunday, Erdogan spokesman Ibrahim Kalin called on Netanyahu to "end the lawless occupation of Palestinian lands and the brutal oppression of Palestinian people."