The suspects, allegedly members of the rebel Kurdistan Workers' Partyhad come to Istanbul to carry out "sensational attacks" after being trained in guerrilla camps abroad, Anatolia news agency quoted police chief Celallettin Cerrah as saying.

The explosives were seized in a bag that two of the suspects carried when they were arrested, Anatolia reported.

The PKK, blacklisted as a terrorist group by Turkey as well as the European Union and the United States, has attacked government and touristic targets in the past.

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