A police officer twisted an elderly woman’s arm during a mass demonstration in Turkish megacity Istanbul, as Kurds and allies protested Sunday’s attacks against Kurdish politician Ferhat Encü.

The incident occurred on Monday, but went viral when the Peoples’ Democratic Party (HDP) Istanbul Co-chair Encü shared a still from a video showing the incident on Tuesday, sparking outrage among social media users.

Encü, a former HDP MP and survivor of the 2011 Roboski massacre, was attacked by another officer on Sunday, during another demonstration. As Encü read out the press statement against police targetings of prisoners’ families, one officer got into an argument with the politician and slapped him across the face.

“When humanity, the law, international treaties, and everything else ends,” prominent human rights lawyer and co-chair to the Human Rights Association (İHD) Eren Keskin said in a tweet.

“Question your humanity if you don’t feel shame and rage when looking at the tyranny against this 70 year old mother,” HDP MP Mahmut Toğrul said.