ISTANBUL: Police detained dozens of protesters across several cities on Thursday after Turkey brushed aside US condemnation of President Recep Tayyip Erdogan's crackdown on a month of escalating student rallies.

AFP reporters witnessed police use riot shields and batons to break up an unsanctioned event in Istanbul and lead away more than 20 people.

Security forces also set up ID checks at two major ports on the Asian and European sides of the Bosphorus to prevent protesters from gathering for the events.

A crowd of leftist political forces and a few opposition lawmakers had come out in support of students protesting Erdogan's decision to name a party loyalist to head Istanbul's elite Bogazici University last month.

Many students see Melih Bulu's appointment as a part of Erdogan's broader push to seize control of various facets of Turks' daily lives while in power for the past 18 years.

Student support groups on Thursday also reported at least 36 people were detained at rallies in the western cities of Bursa and Canakkale as well as the Black Sea port of Samsun.

The students' ability to thrust their demands into the centre of Turkish politics and turn their cause into a national movement have echoes of 2013 demonstrations that first rattled Erdogan's rule.