Berlin - Berlin's central Kreuzberg district cleaned up Saturday after a night where leftist and minority youths battled for hours with riot police under cover of darkness in an annual May Day ritual that began in 1987.

The Berlin riot began Friday evening when about 400 masked militants in a crowd of 5,000 anti-capitalist demonstrators began hurling stones and bottles soon after the parade began. Police dispersed the crowd and tried to catch the offenders.

Police deployed tear gas and pepper spray during hours of running battles. The rioters, assisted by minority youths, beat up lone policemen, set fire to trash and vehicles and smashed windows.

There were large numbers of injured, and medical aid was hampered when stones were also thrown at ambulance crews in the capital. Ordinary firefighters were unable to put out the small fires, so police took on that task too.

A sociologist, Dieter Rucht, rejected suggestions that the fighting represented an upwelling of discontent among the poor amid world recession, saying it was a 22-year-long tradition observed by a militant leftist counterculture numbering about 5,800 Germans.

Berlin professor Rucht accused the media of egging on the violence by predicting the recession would lead to bloodshed.

"If no confrontation had developed, the public could have concluded the militants were weak. From their point of view, they had to act," he said. Police confirmed the Berlin rioting had been fiercer than in recent years.

Sources estimated there were about 200 arrests in the capital.

Some 6,000 riot police were deployed for Berlin's second night of violence after clashes had begun Thursday evening, to be followed by brawls with demonstrating neo-Nazis during the daytime Friday.

May Day is Europe's labour day, with trade unions and left-of-centre parties holding orderly parades. In recent years, neo-Nazis and the extreme left have used the workers' holiday for their own shows of strength.

On Saturday morning, Berlin sanitation crews cleared up debris and road engineers drew up plans to restore cobbled street surfaces and sidewalk paving ripped up by the rioters as ready ammunition.

In another German city, Hamburg, similar street fighting through the night left a car gutted by fire and led to 20 arrests.

The leftists at the heart of the violence are linked to anarchist movements in several other European cities and are hostile to the police, who they regard as stooges of capitalism. (dpa)