The Taksim Square massacre (Turkish: Kanlı 1 Mayıs, or the Bloody First of May) was an attack on leftist demonstrators on 1 May 1977 (International Workers' Day) in Taksim Square, Istanbul, Turkey. Casualty figures vary between 34 and 42 persons killed and 126 and 220 injured. Over 500 demonstrators were later detained by the security forces, and 98 were indicted. None of the perpetrators were caught, although suspicion soon fell on the Counter-Guerrilla and associated right-wing groups. The massacre was part of the wave of political violence in Turkey in the late 1970s.