Protesters hold makeshift shields ahead of a May Day demonstration in central Istanbul May 1, 2014. (Photo:Reuters)
Protesters shield themselves from tear gas fired by riot police during a May Day demonstration in Istanbul May 1, 2014. (Photo:Reuters)
A protester (C) takes aim at riot police with a slingshot during a May Day demonstration in Istanbul May 1, 2014. (Photo:Reuters)
Fireworks explode near protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square on Thursday. (Photo:Reuters)
Protesters shield themselves as riot police fires tear gas during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
A protester takes aim at riot police with a slingshot during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Protesters shield themselves from tear gas fired by riot police during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Riot police use water cannon to disperse protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer.(Photo:Reuters)
Riot police use water cannon to disperse protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Riot police fires tear gas to push back protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Riot police fires tear gas to push back protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Riot police fires plastic paintball gun pellets to push back protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Protesters shield themselves from police water cannon during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Protesters set up a barricade during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Protesters shield themselves as they advance towards riot police during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer.(Photo:Reuters)
Protesters shield themselves from police water cannon during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Riot police fires tear gas to push back protesters during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Protesters shield themselves from police water cannon during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)
Protesters throw tear gas canister back toward riot police during a May Day demonstration in Istanbul May 1, 2014. Turkish police fired water cannon and tear gas on Thursday to prevent hundreds of protesters from defying a ban on May Day rallies and reaching Istanbul's central Taksim Square, the focal point of weeks of protests last summer. (Photo:Reuters)