Democracy campaigners in Bahrain and politicians around the world are calling for this Sunday's Formula 1 race in the Gulf state to be canceled as violent clashes continue between activists and authorities. What are the issues around the controversy, and how are the sport and its fans reacting?
Why are there calls for this weekend's Grand Prix in Bahrain to be scrapped?
Opposition groups in Bahrain as well as politicians, rights groups and many F1 fans around the world want Sunday's Grand Prix -- which could be watched by a global audience of more than 500 million -- to be canceled while the Gulf state braces itself for more violent demonstrations after months of political unrest.
Protesters see the race as a publicity stunt by the country's rulers to make the nation seem more unified than it actually is. The Bahrain Grand Prix was canceled last year amid a Shiite-led uprising against the Sunni monarchy and a government crackdown in which dozens were killed and hundreds detained.
Nabeel Rajab, an opposition protester, said the demonstrators were not against the Formula One race itself. "We are just against the government or the oppressive ruling elite using that as PR," Rajab said.
In Britain, where many F1 teams are based, opposition leader Ed Miliband said: "Sport and politics generally shouldn't mix, but ... what kind of signal does it send to the world when this grand prix is going ahead, given the concerns there are, given the violence we have seen in Bahrain, given the continuing issues around human rights?
"I don't think it's the right decision to let this grand prix go ahead and I think the government needs to weigh in and express its view."
And opposition politician Yvette Cooper urged British F1 stars Jenson Button and Lewis Hamilton to pull out of the race. "It shouldn't go ahead, I don't think British drivers should go. I think the Formula 1 should not go ahead in Bahrain," Cooper told the BBC.
But UK Prime Minister David Cameron refused to join the calls, insisting it was a matter for the F1 authorities whether the race went ahead. "It is important that peaceful protests are allowed to go ahead," he said.
Why are protests now taking place in Bahrain?
Shiite opposition groups in the Sunni-ruled kingdom say they want equality, and have posted calls on social networking sites for daily protests during the Grand Prix weekend, to focus media attention on their demands.
The government has sought to ban protests in the capital Manama but that has failed to prevent violent clashes in the capital between demonstrators and authorities, who are accused of heavy-handed tactics.
The government has condemned violence on all sides -- saying that any police officers found guilty of heavy-handed tactics would be held to account and that protesters should behave in a civil manner as well.
An Amnesty International report this week says promised reforms in Bahrain are inadequate and fail to provide justice for victims of human rights violations.
Protesters are also demanding the release of jailed activist Abdulhadi al-Khawaja, who has been on hunger strike for more than 70 days. Al-Khawaja, 52, was arrested in April 2011 for his role in anti-government protests that began a month earlier with demands for political reform and greater freedoms for Shiites.
In June, Bahrain found him and seven other Shiite opposition activists guilty of plotting to overthrow the country's royal family.
The government also stands accused of punishing its own national sporting heroes and accusing them of being traitors. International and local human rights groups say three players in the Bahraini national soccer squad were arrested last year, along with more than 150 sportsmen, women and administrators. It is unclear how many remain in jail.
The authorities maintain they were part of illegal, violent protests.
Could protesters disrupt the race or threaten spectators?
This is the big question. Protesters have vowed to protest near the Sakhir circuit, which is about 25 miles (40 kilometers) from Manama, but witnesses there say there is a heavy police presence on the road between the track and the airport.
The unrest makes hosting the race precarious because the racers must pass through some areas where clashes have occurred to get to the circuit, which is in the desert.
On Thursday protesters burned tyres, briefly blocking several main roads leading to Sakhir. A Molotov cocktail exploded late Wednesday near a car carrying members of one F1 team, Force India, during clashes between protesters and security forces. No one was reported injured in the incident.
The incident prompted a team member and a contractor to return home despite reassurances by officials that Bahrain is safe. Bahrain has refused to extend visas of non-sports reporting crews from CNN and other news organizations, saying they cannot stay for the race.
What do F1 drivers and the sport's governing body say?
Formula One's governing body, the FIA, decided last week the race should go ahead, after weeks of speculation. The governing body said its president traveled to Bahrain in November and met "decision-makers and opinion formers, including elected Shiite members of parliament. All expressed their wish for the Grand Prix to go ahead in 2012," it said.