Police in Turkey's capital, Ankara, have prevented a large bomb from exploding, the city's governor said.
Sniffer dogs detected a van stuffed with explosives in the centre of the city, preventing a "possible catastrophe", Governor Kemal Onal said.
Security had been tightened in the city ahead of the sixth anniversary of the 9/11 attacks in the United States.
Bomb attacks against the UK consulate, a bank and synagogues in Istanbul killed more than 60 people in 2003.
Six people were killed in Ankara in May by a suicide bomb blamed on Kurdish separatists.
'Meticulous police work'
Ankara's governor said a large quantity of explosives had been left in the van which had a false licence plate.
It was parked in a multi-storey garage in Kurtulus, a densely populated area of central Ankara.
The garage and nearby houses and businesses were evacuated while the police bomb squad worked to defuse the explosives.
"The meticulous work of the police averted a possible catastrophe," said Mr Onal.
"I do not even want to think about what would have happened if the attack had succeeded."
Security fears were heightened elsewhere in Europe as police in Germany moved to help secure a US air base after a bomb threat was made by telephone.