Reuters TV video shows police wearing riot gear pushing and dragging people. Some were waving rainbow flags as they gathered for the event on a side street off Istiklal street in the heart of the city.
Media reports stated that About 20 people were detained, including a photojournalist.
Turkish authorities have banned several Pride events in recent years, before thousands of people attended the Istanbul street parades.
Turkey has long been a member of the European Union. But the process for EU membership has been deteriorating for years amid tensions over issues. This includes human rights.