ISTANBUL — Turkish authorities have banned a protest vigil marking the forced disappearances of hundreds of people in the country's southeast decades ago.

The Saturday Mothers, an activist group, was set to hold its 700th meeting in Istanbul on Saturday. The group has gathered since 1995 to demand justice for those who disappeared during the ongoing conflict between Turkish security forces and Kurdish insurgents.

The district governor said the sit-in was prohibited because the event was publicized on social media with alleged links to the Kurdistan Workers' Party or PKK, which Turkey considers to be a terrorist organization.

The Demiroren news agency said police used tear gas to disperse protesters who tried to gather on Saturday. Turkey's official Anadolu news agency said there were "many detentions."