Police believe the suspects were planning to detonate remote-controlled devices on the Kordonboyu, a central seafront promenade dotted with restaurants, cafes and shops, the agency said.

Police acted on a tipoff that two people who had served jail time for aiding the separatist Kurdistan Workers' Party (PKK) were bringing explosives to Izmir from the country's mainly Kurdish southeast, Anatolia reported.

The two were detained at the Izmir bus terminal, along with two others who had come to meet them.

Their luggage contained 3.5 kilograms of plastic explosive and six detonators, the agency said.

Police then raided a house in Izmir and detained two more men, already wanted for suspected links to the PKK and believed to be the recipients of the cargo, the agency said.

Another 300 grams of plastic explosives and a detonator were seized in the house, it said.

A shadowy Kurdish group that calls itself the Kurdistan Freedom Falcons (TAK) has claimed seven bomb attacsk in urban centers this year and threatened to target tourist areas.

Turkish officials say TAK is a front for attacks on civilians of the PKK, considered a terrorist organization by Turkey, the European Union and the United States.

The bloodiest attack claimed by TAK so far was the July 2005 bombing of a minibus in the popular resort of Kusadasi, near Izmir, in which five people were killed, among them a British and an Irish tourist.

The Kurdish conflict in Turkey has claimed more than 37,000 lives since 1984, when the PKK took up arms for Kurdish self-rule in the southeast.