Turkish anti-riot police on Sunday blocked protests in Istanbul and the Kurdish-majority southeast against Ankara's military operation inside Syria.
At least seven people were detained in Kadikoy on the Asian side of Istanbul, an AFP photographer at the scene reported.
One protester was seen with his hands tied behind by the police officers with others were carried roughly away.
The rally had been called by the pro-Kurdish Peoples' Democratic Party (HDP), whose members are facing a series of legal challenges for alleged ties with the outlawed Kurdistan Workers' Party (PKK).
The police action followed President Recep Tayyip Erdogan's warning of a "heavy price" for anyone joining protests against the Turkish army's operation to oust Syrian Kurdish militia from northern Syria.
It came a day after Turkey launched its operation with Ankara-backed Syrian rebels to root out the Syrian Kurdish Peoples' Protection Units (YPG) militia from Afrin.
Turkey views the YPG militia as "terrorists" linked to the PKK, which has fought against the Turkish state since 1984 and is designated as a terror group by Ankara and its Western allies.
In the Kurdish-majority southeastern city of Diyarbakir, police also blocked a protest, surrounding the HDP headquarters and preventing party officials from making a press declaration, an AFP journalist in the city reported.
"People in Afrin will defend themselves. Turks ... will not gain anything, it is impossible. I call on the international community ... to stop Turkey," protester Hakki Karagoz said.