ANKARA    -   Turkey has no choice but to act alone given too little progress has been made with the United States forming a “safe zone” in northeastern Syria, President Tayyip Erdogan said on Tuesday in his most direct indica­tion of a cross-border of­fensive. After eight years of war in neighbouring Syria, Ankara and NATO ally Washington have agreed to establish a zone along 480 km (300 miles) of the border that Turkey wants to be 30 km deep. Under the Turkish plan, up to 2 million Syr­ian refugees would be settled in the area that would be cleared of the Syrian Kurdish YPG mili­tia, which Ankara deems a terrorist organisation. Since agreeing to set up the zone in northern Syr­ia, Turkey has repeatedly warned of unilateral mili­tary action if efforts do not meet its expectations, saying it would not toler­ate any attempts by Wash­ington to stall the process. It set an end-September deadline for action.