ISTANBUL : Istanbul braced for a major security lockdown for May Day, with almost 25,000 police on duty and numerous roads closed for an occasion that regularly sees clashes between Turkish protesters and police. The Istanbul governor's office said in a statement Saturday that in order "to provide for the security of citizens" on Labor Day, 24,500 members of the Turkish security forces would be on duty in the city. The metro station on the main Taksim Square will be completely closed and the station at the end of the main shopping street Istiklal Caddesi will be closed to exiting passengers.

Security measures are already evident in Taksim Square -- a focus for protests in the past -- with metal security barriers lining the roads and dozens of anti-riot police present, an AFP correspondent said. Numerous roads -- in particular those leading to Taksim -- will also be closed, it added. The authorities, as in previous years, have refused to allow a sanctioned protest to take place on Taksim Square, meaning clashes are highly probable.

The May Day is taking place at a period of particular tension in Turkey after a succession of deadly attacks this year blamed on jihadists and Kurdish militants.

Controversy is also growing over the rule of President Recep Tayyip Erdogan, who critics accuse of increasingly authoritarian tendencies. Several foreign missions have warned their citizens over the risk of violence in Istanbul on May 1, with the US embassy warning of the "potential for violent confrontation between demonstrators and security personnel".