Turkish police on Sunday tightened security around Istanbul's Taksim square, on the second anniversary of the mass anti-government protests that rocked the square in 2013.
Police blocked major roads leading to the square and the adjoining Gezi Park, and public transport links in the area were suspended, an AFP photographer said.
Riot police backed by water cannon trucks were deployed to quell any protests.
The 2013 demonstrations began on May 31 after trees were unrooted as part of a government plan to redevelop Gezi Park. The demonstrations soon snowballed into mass protests, centred on Taksim, over the perceived authoritarianism of President Recep Tayyip Erdogan, who was premier at the time.
The unrest, which represented the biggest challenge to the ruling Justice and Development Party (AKP) since it came to power in 2002, was quelled by the police with copious amounts of tear gas and water cannon.
The heavy-handed police action earned Turkey a strong rebuke from its Western allies.
Erdogan condemned the protesters as "terrorists" out to undermine the state and has warned the government will take a tough line against street protests.