Police in Istanbul on Saturday blocked a weekly demonstration by Turkish mothers demanding state accountability over the fate of relatives who disappeared in the 1980s and 1990s.
The women known as the "Saturday Mothers" have gathered almost every week since 1995.
But on Saturday police put up barricades near their regular Galatasaray Square meeting place and on the famous Istiklal Avenue to stop them assembling following a ban by the Istanbul governor, an AFP photographer said.
Istanbul authorities had said the rally was banned after calls to attend were made through social media channels linked to the outlawed Kurdistan Workers Party (PKK).
As the mothers held carnations and images of the disappeared, a press statement was read out describing the ban as "arbitrary", the photographer added.
Activists say hundreds disappeared allegedly at the hands of the state, at a time when Turkey was fighting Kurdish militants as well as left-wing extremists.
The action by police came after security forces forcibly dispersed the demonstration last week using water cannon and fired tear gas.
Dozens were detained as the mothers marked their 700th weekly demonstration. They were later released.
The group is mainly made up of mothers of victims. Their main demands include access to documents in state archives to shed light on what happened to their relatives and for the statue of limitation to be removed on political murders and forced disappearances.
The disappearances happened during political instability following a 1980 military coup when many were detained for political activism and also during the 1990s insurgency by the Kurdistan Workers' Party (PKK) for self-rule in the Kurdish-dominated southeast.