The scene is not a pretty one.
Despite the Turkish government's ban on demonstrations in Taksim Square in central Istanbul, unions and opposition activists said they would gather there for May Day rallies. Taksim Square has been the scene of anti-government protests since the summer of 2013.
Prime Minister Tayyip Erdogan, who warned last week against efforts to march on Taksim, has cast both last year's street protests and a corruption scandal dogging his government since December as part of a plot to undermine him.
But a joint statement from the main trades unions on Wednesday said:"We will be in Taksim despite the irrational and illegal ban. All roads will lead to Taksim on May Day".
The protesters built barricades and used slingshots to launch stones at the police.
The police fired tear gas, used water cannons and shut down main streets to disperse hundreds of protesters. They also deployed specially designed, portable, steel walls for the first time. The barriers are equipped with cameras and spray tear gas automatically when they are pushed against.
Some activists threw Molotov cocktails and fireworks at police officers, who retaliated with rubber bullets, tear gas and water cannon.
“I have already seen a few people injured,” said RT correspondent Sara Firth, who was caught in tear gas and water cannon fire whilst trying to film on the streets of Istanbul. “It shows no signs of letting up at the moment.”
“This is fascism, this is Erdogan’s obsession about power, nothing else,” said Funda Keles, director of a medical workers’ labor group, as she treated protesters.
“Today our mission is to get to the square. If we run from the gas then we’ll never get there and we would have come here for nothing,” said Can Savas, 24, a student.
The tear-gassing was so intense in the Besiktas district that some families were forced to evacuate their homes. At least 138 people have been detained by police and 51 people have been injured during the protests.
MAY DAY=SHAME DAY in TURKEY please protest with us against Police Fascism pic.twitter.com/OPbQpv83oe— Slonate54 (@Gusha53) May 1, 2014