Some 25 people raided the headquarters of Public Employees Union (Kamu-Sen) and threatened the chairman İsmail Koncuk after beating private security personnel at the building on Tuesday.

The angry crowd chanted slogans against Koncuk’s recent objection to the President Recep Tayyip Erdoğan’s plans to boost his presidential powers.

According to Yeniçağ daily, the group had a discussion with Koncuk and threatened him before demanding his resignation.

The attack came days after the chairman said he would vote “No” in the upcoming referendum that is set to grant more powers to Erdoğan.