protesters shut down Oakland port

Thousands of anti-corporate greed demonstrators have closed one of America's busiest ports.The authorities at the Port of Oakland in California said maritime operations had effectively halted.The shutdown capped a day in which hundreds of city workers, including teachers, joined the call for a strike.The crowds also stopped traffic at a junction where a military veteran was seriously injured last week as protesters clashed with police.Ex-Marine Scott Olsen, 24, is recovering in an Oakland hospital after being struck on the head with a tear gas canister fired by police.That incident catapulted Oakland, which is on San Francisco Bay, to the centre of the national Occupy Wall Street movement and has spurred fresh demonstrations across the US.Organisers of the latest Occupy Oakland protest said they wanted to disrupt operations at the nation's fifth busiest port, which handles about $39bn (£24bn) a year in imports and exports."At this time, maritime operations remain effectively shut down," the Port of Oakland officials said at a news conference late on Wednesday.They said operation would "resume when it is safe to do so".Oakland police estimated that about 3,000 demonstrators were gathered at the port. Police said 4,500 people had marched across the city on Wednesday.But a spokesman for the protest movement, who only gave his name as Aaron, told the BBC: "It is an order of magnitude larger than any protests we've seen and we've seen some big ones in the last week.""There are pockets here and there going on for what seems like miles. I have heard people say 20,000, 30,000... it's impossible to tell."But city officials later said that only about 150 protesters remained at the port late on Wednesday night and some 900 in the city's main square.A number of businesses, including several banks, were shut during the protests, which were largely peaceful during the day, with low police visibility. There were no arrests or injuries.The city officials stressed that there were isolated incidents of violence led by groups of anarchists among the protesters.Oakland Mayor Jean Quan, who had been criticised for her handling of earlier protests, called for calm.However, she said the authorities would "act if we need to maintain safety".The demonstration, which included students, families with young children and union members, began with a rally outside city hall.One large protest banner read: "Occupy Everything, death to capitalism."Oakland officials said about 5% of employees had taken the day off, including about 360 teachers.One teacher at the rally, Brother Muziki, told AFP news agency: "Our classrooms are overcrowded. The banks are being bailed out - but not the schools."The BBC's Alastair Leithead in Los Angeles says Oakland has a higher than average unemployment rate and suffered badly during the US recession.The activists have been protesting against a system which they believe favours corporations and the nation's wealthiest 1%.