Riot police have used teargas and water cannon to break up a gay pride parade in Istanbul.

It's understood officers began the clamp down before the march began in the Turkish city.

The organising committee said several streets leading to the area where the event was to take place have been closed off by authorities.

Being attack by police and still waiving their #Pride flags Remember, this is why we march. Istanbul #Pride pic.twitter.com/bjrBoEWib4

— DCHomos (@DCHomos) June 28, 2015

What a shame. This is unacceptable, ridiculous and inhuman. Stop it. #istanbulpride pic.twitter.com/inbxMAYaES

— デニセ (@dxnyse) June 28, 2015

The organisers of Pride week have remained defiant:

WE ARE HERE, WE ARE NOT LEAVING, GET USED TO IT

— LGBTÄ° Onur Haftası (@istanbulpride) June 28, 2015