Protesters and Brazilian police clashed in Sao Paulo, Rio de Janeiro and at least three other World Cup cities on the opening day of the football tournament.

In Sao Paulo, more than 300 demonstrators gathered along a main highway leading to the stadium. Some tried to block traffic, but police repeatedly pushed them back, firing canisters of tear gas and using stun grenades. The flow of traffic to the arena was not blocked.

Protesters gathered near a subway station west of the stadium. A few protesters suffered injuries after being hit by rubber bullets, while others were seen choking after inhaling tear gas. An Associated Press photographer was injured in the leg after a stun grenade exploded near him. CNN reported that two of its journalists were also injured.

world cup protests brazil 2014 Sao Paulo
A policeman shoots tear gas at protesters during a demonstration against the 2014 World Cup in Sao Paulo, Brazil.Reuters
world cup protests brazil 2014 Sao Paulo
Associated Press photographer Rodrigo Abd, who was injured by riot police, is assisted during a protest against the 2014 World Cup in Sao Paulo.Reuters
world cup protests brazil 2014 Sao Paulo
A military police officer reacts after police released tear gas to disperse demonstrators at the entrance of Tatuape metro station during a protest against the 2014 World Cup in Sao Paulo.Reuters
world cup protests brazil 2014 Sao Paulo
Demonstrators from the anarchist group Black Bloc clash with police in Sao Paulo.Getty
world cup protests brazil 2014 Sao Paulo
Black Bloc demonstrators empty a fire extinguisher during a protest against the World Cup at Tatuape metro station in Sao Paulo.AFP
world cup protests brazil 2014 Sao Paulo
Demonstrators clash with police on the opening day of the World Cup in Sao Paulo.Getty
world cup protests brazil 2014 Sao Paulo
A demonstrator juggles in front of a line of riot police during a protest against the World Cup at Tatuape metro station in Sao Paulo.AFP
world cup protests brazil 2014 Sao Paulo
A police officer runs with a pistol in his hand after clashes with demonstrators outside Tatuape station in Sao Paulo.Reuters

Just after the opening match started, about 300 protesters demonstrating against the World Cup marched along Rio's Copacabana beach and stopped outside the Fifa Fan Fest — a closed and secured area on the beach where hundreds of fans were watching the match on a massive screen.

The protest was peaceful, but there were worries that violence could break out as adherents to the anarchist Black Bloc were seen among the demonstrators.

world cup protests brazil 2014 Rio de Janeiro
An anti-government demonstrator dressed as Batman stands with a sign on the Lapa Arches in Rio de Janeiro.Reuters
world cup protests brazil 2014 Rio de Janeiro
A demonstrator dressed as Batman yells slogans, accompanied by passengers on a bus, in Rio de Janeiro, holding a placard saying: 'We want to be the champions in healthcare, education and not just in football.'Reuters
world cup protests brazil 2014 Rio de Janeiro
A demonstrator shows her disdain for the World Cup in Rio de Janeiro.Reuters
world cup protests brazil 2014 Rio de Janeiro
People protest in front of police during an anti-World Cup demonstration in Rio de Janeiro.Getty
world cup protests brazil 2014 Rio de Janeiro
Riot police are seen behind an anti-Fifa banner at the fan area on Copacabana Beach in Rio de Janeiro.AFP
world cup protests brazil 2014 Rio de Janeiro
Riot police advance to clear the street of protesters in the vicinity of the Fifa Fan Fest area at Copacabana Beach in Rio de Janeiro.AFP
world cup protests brazil 2014 Rio de Janeiro
Medics help an injured young man during an anti-World Cup protest at Copacabana beach in Rio de Janeiro.Getty

In Belo Horizonte, another Cup host city, about 200 protesters clashed with police. Some demonstrators smashed the glass doors and windows of two banks. The protest started peacefully but escalated, with the violence forcing at least one nearby hotel to shut its doors and ask guests not to go outside.

world cup protests brazil 2014 belo horizonte
Riot police are deployed during a demonstration against the 2014 World Cup in Belo Horizonte.AFP
world cup protests brazil 2014 belo horizonte
Youths gesture during a demonstration against the World Cup in Belo Horizonte.AFP
world cup protests brazil 2014 belo horizonte
A shopkeeper peeps out from a damaged shutter during a protest against the World Cup in Belo Horizonte.AFP
world cup protests brazil 2014 belo horizonte
Police arrest a young demonstrator with a skateboard in Belo Horizonte.AFP

Porto Alegre, another host city, saw about 1,000 people gather for a protest against the Cup. Black Bloc demonstrators smashed the windows of a few businesses, including a McDonald's restaurant. A group started to march toward the city's Fifa Fan Fest area, but police dispersed them with tear gas and rubber bullets.

world cup protests brazil 2014 porto alegre
Riot policemen stand in front of a torn Brazilian flag during a protest against the 2014 World Cup in Porto Alegre.Reuters
world cup protests brazil 2014 porto alegre
A detained demonstrator stands against a wall during a protest in Porto Alegre.Reuters