Police in Istanbul have detained more than a dozen demonstrators who tried to march toward Istanbul's symbolic main square in defiance of a ban.
Turkey declared Taksim Square off-limits to May Day celebrations citing security concerns.
Roads leading to the square were blocked and police allowed only small groups of labour union representatives to lay wreaths at a monument there.
Still, a group of some 25 people, chanting "Taksim cannot be off limits on May 1" tried to push their way into the square but were rounded up by riot police.
Major trade unions were scheduled to mark the day with rallies at government-designated areas in Istanbul and Ankara.
Taksim holds a symbolic value for Turkey's labour movement.
In 1977, 34 people were killed there during a May Day event when shots were fired into the crowd from a nearby building.