Turkish police charged into crowds of leftist protesters marking the anniversary of a deadly May Day rally in Istanbul on Tuesday, spraying tear gas and kicking and clubbing demonstrators as they fled. Police also used a water cannon to clear crowds from around Taksim square. Officers outfitted with helmets, gas masks and truncheons detained 580 demonstrators. Some of the protesters were carrying pistols, firebombs and knives, Istanbul Gov. Muammer Guler said. Authorities had declared the area off limits to protesters but allowed a few hundred of them to lay red carnations at the square, where unidentified gunmen opened fire on tens of thousands of demonstrators during a May Day gathering in 1977. The incident left 34 people dead, most of whom were killed in a stampede. It was the first time authorities allowed some May Day protesters, including union officials, to enter the square since the 1980 military coup. Police prevented hundreds of others from reaching the square.