President Recep Tayyip Erdogan today threatened to expand Turkey's offensive in Syria against a Kurdish militia, despite rising concern and calls for restraint from the US and other Western allies.<br/>'<br/>In the seventh day of the operation against the Syrian<br/>Kurdish People's Protection Units (YPG) militia, Erdogan vowed<br/>to "clean up" the Syrian city of Manbij.<br/>'<br/>The United States has raised concerns over the deadly offensive, and analysts say direct military conflict between the two NATO powers is possible since the US has a military presence in Manbij. While the YPG is still working closely with Washington against the Islamic State extremist group in Syria, Ankara views the YPG as a terror organisation allied to the outlawed Kurdistan Workers' Party (PKK) inside Turkey.<br/>'<br/>The PKK is blacklisted by Ankara and its Western allies as a terror outfit.<br/>'<br/>'''''''<br/>