Sixteen militants planning to bomb next month’s Nato summit in Istanbul have been arrested, Turkish police say.
Police in the north-west city of Bursa said the suspects were members of the radical Islamic group Ansar al-Islam, believed to have links to al-Qaeda.
One report said guns, explosives and 4,000 compact discs of training advice from Osama Bin Laden were seized.
US President George W Bush and other world leaders are due at the summit being held on 27 and 28 June.
The governor of Bursa, a city 250 km (160 miles) south of Istanbul, is expected to make a detailed statement later.
With up to 50 world leaders scheduled to attend, Turkey is under pressure to ensure security is water-tight for the Nato summit.
Fears of attacks have been heightened since the four suicide bombings in Istanbul last November.
Sixty-two people were killed and hundreds injured when two synagogues, the British consulate and HSBC bank were targeted in Turkey’s largest city.