Brazil's President Dilma Rousseff formally launched her re-election bid on Saturday, leading in opinion polls despite lingering discontent over World Cup costs.

Her leftist Workers Party (PT) approved her candidacy in a voice vote of 800 members meeting at a convention in Brasilia, with the popular former president Luiz Inacio Lula da Silva on hand.

Brazil's Julio Cesar on Thursday jumped to the defense of fellow goalkeeper Iker Casillas, after the Spain captain was heavily criticized for his part in the World Cup holders' shock early exit.

A Spain side whose recent successes were built from their solid defense have crumbled at this World Cup, losing to both the Netherlands and Chile and conceding seven goals in the process, some of which were blamed on Casillas.

An Air Canada flight to Brazil packed with World Cup fans was forced to turn back to Toronto Thursday after authorities learned that a man had sneaked onboard.

Air Canada 090 was already over the Caribbean and four hours into the flight when Transport Canada ordered its return to the Toronto International Airport, said officials and witnesses.

U.S. Vice President Joe Biden, on a four-country trip across Latin America, said he hoped the region would accept more Guantanamo prisoners to help expedite closing the facility, in an interview published Wednesday by a Colombian newspaper.

"One of the fastest ways to accelerate the closure of Guantanamo is for other countries to agree, in a responsible manner, to receive detainees," Biden was quoted as saying in the Spanish-language El Espectador.

U.S. Vice President Joe Biden said Tuesday after meeting Brazilian President Dilma Rousseff that he was confident the two countries could improve relations damaged by revelations of American spying.

Biden is in Brazil to patch up ties strained by reports of U.S. spying on Rousseff's personal phone and email communications, leaked last September by fugitive National Security Agency contractor Edward Snowden.

Police fired rubber bullets and arrested 11 people Monday to break up anti-World Cup protesters who trashed banks and blocked traffic in the southeast Brazilian host city of Curitiba.

About 200 protesters gathered in the city center and marched toward the stadium where Iran played Nigeria in a World Cup match, but were blocked by police, news website G1 reported.

While World Cup referees finally have goal-line technology to prevent mistakes, doctors in Brazil will soon have their own computer gizmo to contain dengue outbreaks.

In the tropical northeastern city of Natal, a new smartphone application could allow residents to alert authorities about the location of concentrations of mosquitos and cases of dengue with the touch of a finger.

Brazilian police made 11 arrests and used tear gas to disperse anti-World Cup demonstrators Friday in the northeastern city of Salvador.

Military police told AFP the arrests had been for "vandalism" in the city located just five kilometers (three miles) from the Fonte Nova stadium where the Netherlands beat reigning champions Spain in their opening group match.

Pope Francis admitted in an interview Friday that he takes a risk when he ditches a "sardine can" popemobile to greet the people, but at his age he has little to lose.

The 77-year-old pontiff recalled that for his July 2013 visit to Brazil officials had prepared a glass-enclosed "popemobile" to shield him.

From the Amazon rainforest to Brazil's vast northeastern coast and bustling cities, throngs are gearing up to finally celebrate, and protest, the World Cup.

The tournament kicks off with Brazil taking on Croatia in the business hub of Sao Paulo on Thursday before teams from 32 nations criss-cross 11 other cities scattered across the massive South American country.