Diplomatic tensions between the U.S. and Turkey over comments made by U.S. Vice President Joe Biden on Turkey's role in Syria.<br/> <br />Biden said Turkey and other regional countries had been so determined to topple Syrian President Bashar al-Assad that they had supported extremist groups including al Qaeda and al Nusra Front.<br/> <br />Now outrage from Turkish President Tayyip Erdogan.<br/> <br />(SOUNDBITE) (Turkish) TURKISH PRESIDENT, TAYYIP ERDOGAN, SAYING:<br/> <br />"If Biden has used such expressions he will be history for me. I have never made those remarks. Neither at that time when I was the Prime Minister, nor today, we have never provided help and support to any terrorist organization - I say terrorist organization - including the Islamist State. Nobody can prove otherwise."<br/> <br />In an address to Harvard University students last week Biden said Erdogan told him they had made a mistake by letting so many foreign fighters through the Turkish border to fight Assad's forces.<br/> <br />(SOUNDBITE)
