Istanbul , Turkey ( CNN ) -- Turkish security forces barricaded the commercial center of Istanbul in an attempt to stop May Day celebrations from taking place in the city 's iconic Taksim Square . Police fired plastic pellets and used tear gas and water cannon in an attempt to disperse May Day demonstrators who tried to defy the ban and reach the city center . Protesters responded by throwing stones and bottles and shooting fireworks at riot police . Similar clashes erupted in the Turkish capital Ankara and the port city of Izmir . Turkish authorities went to great lengths to prevent people from gathering in Istanbul , Turkey 's largest city . Citing security threats by extremist groups , the government shut Istanbul 's subway system , stopped many commercial ferry services between the European and Asian halves of the city , and blocked vehicular traffic on some of Istanbul 's busiest roads . `` Intelligence units have received information that illegal terrorist organizations and their extensions are going to resort to violence against security forces . This situation would create circumstances that would not only disrupt public order and security but also seriously threaten the rights and freedoms of our citizens , '' the Istanbul governor 's office announced in a written statement released Wednesday night . The governor 's office also justified the ban , arguing that May Day rallies would hurt Istanbul 's image as a tourist destination . `` Taksim Square and the surrounding area are not suitable for high attendance gatherings and demonstrations , '' the governor 's office wrote . `` In Taksim vehicular and pedestrian traffic is intense and the area has great tourism potential with 24/7 tourist hotels , so negative developments in this area would negatively impact the country economy , tourism potential and the marketing image of our country . '' But the shut-down of the city center left many foreign tourists bewildered , as police turned them away from barricades . Some visitors could be seen dragging suitcases through empty and barricaded streets in a confused search for hotels . `` Closed , '' a police officer said , turning away an elderly European couple trying to enter Taksim Square . The sprawling pedestrian area was all but deserted throughout the day on Thursday , with the exception of security forces , a handful of journalists , and wandering flocks of pigeons . For decades , May Day , or International Workers Day , has been a day of tension between leftist Turkish labor unions and security forces . Taksim Square holds particular importance to leftist parties , because dozens of people were killed there in a May 1 , 1977 rally in which gunfire triggered a deadly stampede . In 2011 and 2012 , the ruling Justice and Development Party allowed leftist groups to rally in Taksim for the first time in decades . The gatherings were festive and peaceful , decorated with giant posters of those who died in 1977 . But in 2013 , the government banned the annual rally , sparking a day of violence that has spiraled into the most politically turbulent year of anti-government protests Turkey has seen in more than a decade . Turkey 's Prime Minister Recep Tayyip Erdogan has been in power since his party first won parliamentary elections in 2002 . He frequently denounces his critics , accusing them of being terrorists bent on overthrowing his government . His supporters argue Turkey has grown more democratic during the Erdogan era . They point to his party 's sweeping victory in local elections last March , when Justice and Development Party candidates won at least 43 % of the national vote . `` We have moved away from a state that saw its citizens as a threat , '' said Deputy Prime Minister Besir Atalay in a speech earlier this week . But many human rights groups and press freedoms organizations argue the Erdogan government has grown increasingly intolerant of public displays of dissent in recent years . This week , the U.S.-based human rights organization Freedom House downgraded classification of Turkey from `` Partly Free '' to `` Not free . '' `` Constitutional guarantees of freedom of the press and expression are only partially upheld in practice , undermined by restrictive provisions in the criminal code and the Anti-Terrorism Act , '' Freedom House said . They also said , `` Turkey remained the world 's leading jailer of journalists in 2013 . ''
Turkish authorities went to great lengths to prevent public gatherings in Istanbul . They used tear gas and water cannon to disperse demonstrators who defied ban . The government also banned the use of social media by protesters, which led many people to take to Twitter or other forms of communication to organize protests against the government.