( CNN ) -- U.S. Vice President Joe Biden apologized to Turkey 's leader on Saturday for saying that President Recep Erdogan admitted his country had made mistakes allowing foreign fighters to cross into Syria . The apology came hours after Erdogan expressed his anger over the comments to reporters in Istanbul , saying `` Biden has to apologize for his statements . '' Or Biden , he said , will become `` history to me , '' according to published reports by the semi-official Anadolu news agency . The problem appears to have originated during a question-and-answer session following a speech this week at the John F. Kennedy School of Government at Harvard University when Biden was asked about Turkey and the threat posed by the so-called Islamic State terror group , known as ISIS or ISIL . `` President Erdogan told me , he 's an old friend , said , 'You were right . We let too many people through . ' Now they are trying to seal their border , '' he said , according to transcripts . Erdogan vehemently denied ever saying such a thing . `` The Vice President apologized for any implication that Turkey or other Allies and partners in the region had intentionally supplied or facilitated the growth of ISIL or other violent extremists in Syria , '' Biden spokeswoman Kendra Barkoff said . `` The Vice President made clear that the United States greatly values the commitments and sacrifices made by our Allies and partners from around the world to combat the scourge of ISIL , including Turkey . '' During their telephone conversation , Biden and Erdogan reaffirmed the two countries ' commitment to fight the terror group , Barkoff said . Erdogan 's office and the Turkish Foreign Ministry did not immediately respond to a CNN request for comment regarding Biden 's apology . The issue has arisen at a sensitive time , with Turkey 's government authorizing the use of military force against terror groups , including ISIS as its fighters laid siege to towns just south of the Turkish border . The government also agreed to allow foreign troops to launch operations against ISIS from Turkey . Until now , Turkey has offered only tacit support to the coalition . While Biden is known for making blunt statements that sometimes embarrass the administration , Turkey is particularly sensitive to allegations of allowing terrorists to cross its border into Syria . Syrian President Bashar al-Assad has accused Turkey of looking the other way and , in some cases , providing support to rebels embroiled in the country 's civil war . Turkey , in turn , has accused Syria of fomenting the unrest that has led to ISIS taking hold in the region . CNN 's Talia Kayali and Tom Dunlavey contributed to this report .
Turkey 's President Recep Erdogan demanded an apology from Vice President Joe Biden . Erdogan was angered by comments Biden made . The Turkish leader said the vice president had insulted his country and called him a "terrorist" in remarks that were broadcast on state television. Erdogan told reporters Biden must apologize or he will be `` history to me ''