ISTANBUL – Turkish riot police fired water cannon and tear gas in clashes with May Day demonstrators in Istanbul on Friday.

Young men hurled stones and Molotov cocktails at the police and smashed windows of banks and supermarkets in side streets. The police fired warning shots and pepper gas to disperse groups of masked protesters.

One police officer and one demonstrator were injured, Istanbul Governor Muammer Guler said, and several demonstrators were detained. Leftists and Kurdish separatists frequently clash with the police at demonstrations.

Thousands of police regulated access to the city's main Taksim square, which has been closed to workers' demonstrations since 37 people died in a shooting by an unknown gunman or were trampled to death on May Day in 1977.

Police let thousands of labor union members pass through checkpoints into the square where union leaders made speeches to the crowd, but they later made the demonstrators leave.

Public offices and financial markets are closed on Friday for May Day. Turkey's government declared it a public holiday this year under pressure from labor unions, at a time of heightened financial difficulties and record unemployment.

Those who are here are unemployed and need work. These are students who cannot pay tuition fees. Things are bad everywhere but it hits Turkey hard, said Mehmet Guleryuz, a film director.

Almost one in three young people is without a job and the government fears social unrest and increased ethnic tensions because of the economic downturn.

These are not workers and they have nothing to do with workers. These are radical groups and separatists provoking the police, Guler said. But Friday's parade was more peaceful than those in previous years, he said.

Last year's May Day clashes turned violent and police detained hundreds of people after trade unions had pledged to mobilize up to 500,000 people in defiance of an official ban.

Labor Minister Faruk Celik criticized the violence. May 1 is not a day for battle and war...Everyone should respect the authorities' decision not to use Taksim for demonstrations, Celik said.

The trade unions said Taksim had a symbolic value for the Turkish labor movement and ignored the government's pleas to hold demonstrations in other parts of Istanbul.

We have come here today because there is a score that needs to be settled from 1977, said Adem Anli, a 25-year-old municipal worker.