Turkish police used tear gas and water cannon to disperse environmentalist protesters marching against a planned copper mine on Sunday.
The demonstrators set off from the north-eastern city of Artvin with the intention of reaching the construction site of the mine, but were blocked by security officials, according to broadcast reports from IMC TV, which is critical of the government.
Some of the protesters attempted to breach the police defence and kicked officers' riot control shields, video footage broadcast by CNN Turk showed.
Green activists have been protesting the new copper mine for a week, claiming that it would cause irreparable damage to the local environment.
Prime Minister Ahmet Davutoglu, in comments to the state-run Anadolu agency, insisted that care would be taken in building the mine.
However, he vowed to crack down on environmentalists who want to "provoke" and hijack the issue as a means of government criticism.