The arrest of Turkish troops by US forces in northern Iraq has caused a "crisis in relations" between the two Nato armed forces, according to the chief of Turkey's armed forces. The 11 soldiers were returned by helicopter from Baghdad on Monday to their base in the northern Iraqi town of Sulaymaniyah. The arrests led to a weekend of intense negotiations between Ankara and Washington as the Turkish Government sought the men's release. Turkey's Chief of General Staff Hilmi Ozkok said the incident had developed into "a major crisis of trust between the Turkish and US armed forces".