Turkish riot police fired tear gas Saturday to disperse hundreds of protesters in demonstrations against the clearance of trees on an Ankara university campus to make way for a controversial road development.

In one demo by some 100 students, 26 people were arrested as they tried to march to the campus of the Middle East Technical University from Ankara city centre, according to the left-wing student group Genc-Der, which organised the rally.

The protesters were attempting to plant trees in the garden of a public building, the group's representative told AFP, adding that police prevented them from doing so.

In a separate protest later on Saturday, some 200 protesters walked onto the road construction site, prompting police to use tear gas and water cannon to break up the crowd, the private Dogan news agency reported.

For several weeks there have been sporadic protests in Ankara and other cities against the plan to build a road through the campus in a bid to alleviate traffic congestion in the Turkish capital.

Prime Minister Recep Tayyip Erdogan, whose rule was recently hit by an unprecedented wave of protests over an urban development plan in Istanbul, last week denounced those who opposed the project in Ankara as "modern bandits".

The June protests saw an estimated 2.5 million people take to the streets over three weeks to demand the resignation of Erdogan, seen by many as an authoritarian leader trying to force his Islamic values on staunchly secular Turkey. The clashes left six people dead.