SAO PAULO - With all of the issues and questions leading up to the World Cup, Itaquerao Stadium shined under blue skies as Brazil kicked off its home World Cup with a football-style carnival on Thursday.

Jennifer Lopez, rapper Pitbull and Brazilian pop star Claudia Leitte bounced around a giant stage resembling a peeled melon singing "We Are One" on Brazil's Valentine's Day. The field was covered in for the opening ceremony, which cost $8 million US, or about 18 million Brazilian reais.

The scene inside Corinthians Arena was a world apart from the protests just up the road, as more than 600 dancers in colourful costumes joined pop superstars Jennifer Lopez and Pitbull to put on a lavish opening ceremony. Samba dancers, capoeira performers and a drumming collective celebrated the vast South American country's rich cultural diversity as J.Lo and company sang the official World Cup song, "We Are One."

Despite being regarded as the spiritual home of football, Brazil has been slow to embrace World Cup fever. Excitement has built gradually in the days leading to the event, with increasing numbers of Brazilian flags flying from cars, bars and apartment blocks. A giant Brazilian flag was draped at the foot of Rio's iconic Christ the Redeemer Statue on Thursday. But while more Brazilians are sporting the yellow jersey of star forward Neymar, discontent continues to simmer.

The sun rose Thursday on this tropical nation hosting its first World Cup of soccer in 64 years. Nearly half the world's population, well over three billion spectators, is expected to watch soccer's premier event and get a glimpse of the country that in two years will host the Summer Olympics.

Play begins with Brazil and Croatia meeting in Sao Paulo on Thursday Brazilians are hungry to see their soccer juggernaut deliver a record sixth World Cup crown to a nation desiring something — anything — to celebrate after enduring a year of gruelling protests and strikes.

But as play begins, it still isn't clear which Brazil we'll see. Will it be the irreverent nation known for its festive, free-wheeling spirit? Or the country that for the past year has been a hotbed of fury over poor public services, discontent over a political system widely viewed as corrupt and deep anger over the $11.5 billion US spent on hosting the World Cup?

By mid-morning, it looked like it would be both. Protesters and Brazilian police clashed in Sao Paulo on Thursday, with more than 300 demonstrators gathered along a main highway leading to the stadium. Some in the crowd tried to block traffic, but police repeatedly pushed them back, firing canisters of tear gas and using stun grenades.

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 on its website that two of its journalists were also injured.

"I'm totally against the Cup," said protester Tameres Mota, a university student at the demonstration. "We're in a country where the money doesn't go to the community, and meanwhile we see all these millions spent on stadiums." About 300 protesters also gathered in central Rio de Janeiro in another demonstration against the World Cup, though no clashes were reported by early afternoon.

Meanwhile, the streets were filled with fans ready for festivities. "The world is going to see multitudes cheering for soccer — but also demanding that our country change," Helen Santos, a school teacher, said as she walked home in Rio de Janeiro. "The world needs to see that we're a serious country. We're not just a nation of soccer, but a country striving and demanding the government provide better education and health care. The world needs to see the reality of Brazil, not just the sport."

The multi-billion-dollar cost of the World Cup has angered many in a country which has under-funded health and public services, and where violent crime is rampant. Rage at poor public services morphed into a nationwide movement at the Confederations Cup test event, with deadly clashes rippling across the nation. A vast security blanket is being deployed to shield the World Cup from unrest, with 150,000 soldiers and police on duty along with 20,000 private security officers.