Sirin Tekik, Dicle Manap and Celallettin Padir -- all members of the country's main Kurdish party, the Democratic Society Party (DTP) -- were remanded in custody pending trial by a court in Batman late Friday.

The court also issued an arrest warrant in absentia for the DTP's provincial chairman Ayhan Karabulut on the same charges, the sources said.

The arrests followed a raid on the DTP's office in Batman Thursday during which authorities found documents of the outlawed Kurdistan Workers' Party (PKK) and posters of its jailed leader Abdullah Ocalan.

Prior to the raid, the DTP's Batman office had issued a press statement condemning the arrest of three fellow party officials in neighbouring Diyarbakir province over remarks that allegedly threatened violence in Turkey.

Kurdish politicians are routinely suspected by Ankara of supporting the PKK and are often prosecuted for alleged links to the group, which has been fighting for Kurdish self-rule in the southeast since 1984.

The DTP was set up in November 2005, pledging to try to resolve the Kurdish conflict through peaceful means, but has so far made no progress.

It has come under fire for sympathizing with the PKK, which is blacklisted as a terror group by Turkey, the European Union and the United States.