In a petition to parliament's human rights commission, eight DEM lawmakers said "at least 99 minors were detained" in January in connection with Syria protests, the party said in a statement.

Of that number, 25 were formally placed under arrest by a court.

Prosecutors had opened investigations on suspicion of "organised propaganda" over social media posts which should have been covered by freedom of expression provisions, it said.

It cited the case of a 16-year-old detained in Izmir over a hair braiding video and song posted online, who was subjected to a strip search at the city's juvenile detention facilities.

Last month, hair braiding turned into a symbolic show of solidarity with Syrian Kurds as Damascus pressed a military offensive in northeastern Syria as it sought to reassert its authority, sparking protests among Turkey's Kurds.

DEM said some of the minors had been "banned from seeing a lawyer for 24 hours", others suffered "physical violence" during detention, were questioned without the right legal representatives present and "forced to sign documents under pressure".

Others were "forced to endure a strip search" on entering the detention facilities, were "subjected to curses and insults" or had their "hair... cut without their consent".

During the Syria operation, social media was awash with clips of women braiding their hair in response to a video showing a Syrian soldier holding a braid he claimed to have cut from a Kurdish woman fighter -- a claim that could not be independently verified.

The Turkish authorities responded with a crackdown on such posts -- in the northwestern town of Kocaeli, a nurse was detained on grounds of making "terrorist propaganda" but later released under judicial control.

And Turkey's main Kurdish football team Amedspor FC was fined 802,500 Turkish lira (nearly $18,500) for "ideological propaganda" for posting a 20-second braiding clip on its social media accounts.

Its president was also slapped with a 15-day suspension from all football activity, the Turkish Football Federation said.