The operation, under planning since last year, aims to expose those with links to the outlawed Kurdistan Workers' Party (PKK) inside the Democratic Society Party (DTP) and Kurdish non-governmental organizations, the source said on condition of anonymity.

Three deputy chairmen of the DTP were among those held in the operation carried out in more than 10 provinces in Turkey's mainly Kurdish southeast and main cities in its west.

Kurdish politicians in Turkey are routinely accused of supporting the PKK, which has been fighting for self-rule in the southeast since 1984 and is listed as a terrorist group by Ankara and much of the international community.

Some 44,000 people have been killed in the conflict.

The DTP, which is represented in parliament, is currently on trial at the Constitutional Court for alleged links to the PKK and faces the risk of being outlawed.