A US military official confirmed on Sunday that US forces in northern Iraq had detained several soldiers they believed to be Turkish.

Asked about accusations from Ankara that US troops had seized Turkish special forces, the official said: "There was a raid. The US military is still trying to determine their ethnicity but they are probably Turkish."

Turkey's Hurriyet newspaper said around 100 US soldiers grabbed the Turks in the northern city of Sulaimaniya on suspicion of planning an attack on the Kurdish governor in the oil-rich city of Kirkuk about 100 km away.

Turkey's foreign minister dismissed the charge as "nonsense."

Turkish Prime Minister Tayyip Erdogan accused the United States on Saturday of seizing the troops in an "ugly incident" on Friday afternoon. He later said some of them had been freed.

The case threatens to exacerbate tensions between the two NATO allies. Relations were already strained after Ankara refused to allow US troops to stage attacks from Turkish soil during the war on Iraq.