Formula One cars have taken to the track in Bahrain today in the first practice session, as calls continue for the race to be cancelled.
The Bahrain International Circuit is only 25 miles away from the capital Manama, the scene of violent clashes on Thursday. Police used tear gas and stun grenades to disperse around 700 people close to the British embassy.
Activists are promising "days of rage".
Amateur footage has emerged from the Abu Saiba region of Bahrain, reportedly showing clashes between protesters and police on Thursday. ITV News is unable to verify the content and location of the images.
"Formula One in Bahrain has been taken as PR for the ruling elite, the repressive dictators who are ruling the country," activist Nabeel Rajab told a news conference.
Media freedom groups have also accused Bahrain of using this weekend's Formula One motor race as a propaganda exercise to improve its international image, saying it wants to stop journalists reporting on anti-government protests.
Journalists were still waiting for entry visas as Formula One cars took to the track for Friday's first practice session amid tight security.
"Bahrain wants the international attention brought by hosting a Grand Prix but doesn't want foreign journalists to wander from the race track where they might see political protests," said Robert Mahoney, deputy director of the Committee to Protect Journalists in New York.
"Bahrain tells the outside world it has nothing to hide. If that's the case then it must allow journalists entry visas and let them report freely," he added.
The shadow home secretary Yvette Cooper has made her feelings clear. She says the event should be cancelled:
Downing Street said the Government remained "concerned" about the violence in Bahrain, but refused to be drawn on whether the race should go ahead.
"It is not for us to dictate what sporting events happen in other countries," a No 10 spokeswoman said.
Daybreak's Richard Gaisford reports British Formula One drivers are being urged to boycott the Grand Prix in protest at the government crackdown on the growing democracy movement.
Many drivers have been reluctant to speak about the unrest, insisting they were only there for the sport.
Bahrain called off the competition last year amid unrest in a blow to the country's Sunni rulers.
Two members of one of the F1 teams, Force India, decided to leave Bahrain after a team vehicle was caught in a traffic jam on Wednesday caused by a hurled firebomb.
Nearly 50 people have been killed since February 2011 in violence between security forces and protesters from Bahrain's Shiite majority.
They are trying to break the near monopoly on power by the nation's Sunni monarchy.
- Shiites account for about 70% of Bahrain's population
- They claim they face widespread discrimination
- Sunni leaders have offered some reforms
- Opposition says they fall short of their demands
Large sums of money are stake this weekend.
Last year, Bahrain paid a "hosting fee" of $40 million despite cancelling the race.
The Grand Prix drew 100,000 visitors to the nation of just 1.3 million and generated half a billion dollars in spending when it was last held two years ago.