The suspect, believed to be a member of the Kurdistan Workers' Party (PKK), was detained last week after police detected her scouting outside its main headquarters in Istanbul, the report said.

Police believe she was preparing to attack two targets.

The PKK, blacklisted as a terrorist group by Turkey and much of the international community, has been fighting for self-rule in the country's mainly Kurdish southeast since 1984 in a conflict that has claimed about 45,000 lives.

Recent weeks have seen a resurgence of violence in the southeast, the PKK's main theatre of operation, as the arrival of spring allows the rebels to move out of their mountainous bases in Turkey and neighbouring northern Iraq.

The rebels have in the past carried out bombings in cities that have killed civilians.