Violence marred Bahrain's Grand Prix race as a fire bomb exploded near Force India team members and protesters clashed with police in the lead-up to the Formula One practice runs set to begin Friday. Security has been beefed up ahead of Sunday's race, but the incident prompted F1 officials to reassure participants that, despite the violence, Bahrain was safe. Speaking to reporters at the Sakhir circuit, chairman of the Formula One Grand Prix Drivers Association, Pedro de la Rosa, said safety is “not a concern.” He added that he had full faith in the decision by the International Motoring Federation to hold the event despite mounting tensions in the kingdom. Four members of the Force India team were stuck in traffic when a fire bomb exploded as they returned from the Sakhir circuit to their hotel late Wednesday, Bahrain International Circuit chairman Zayed Alzayani told Autosport magazine. The four mechanics apparently got caught up in a clash between protesters and police on the main motor way from the capital Manama to Sakhir. Nobody was injured. A spokesman for the Force India team confirmed the incident and said one team member, not involved in the incident, and a contractor hired by the team, had chosen to return home as a result of the blast. Alzayani played down the matter and said he would not request any tighter security as a result. “It was an isolated incident ... The protesters were not targeting the cars, they just happened to be there,” he said. Force India driver German Nico Hulkenberg said it was “not right” that members of his team had been close to an exploding fire bomb, but added that he still felt safe. Mohammad Mascati, head of the Bahrain Youth Society for Human Rights, told that security forces fired tear gas and sound bombs to disperse dozens who protested in Manama Thursday, adding that police set up checkpoints at the entrances to the capital. Bahrain's main opposition group, Al-Wefaq, has called for a week of daily protests to coincide with the Grand Prix, using the sports event to focus media attention on their long-standing demands. “There is a desire to take advantage of the presence of (international) press, normally barred from entering the country,” said Bahraini rights activist Nabil Rajab. “The Formula One... is a symbol of the regime, it represents its repression,” said Rajab, noting that the Bahrain race is a personal project of the crown prince. Bahraini economist Jasim Husain, who said he resigned from Al-Wefaq last year, said the protests were not connected to the event. “We have had protests taking place before the event, they will take place during the event and afterwards, but there is no connection,” Husain told reporters. The government Thursday barred Al-Wefaq from holding a protest in central Manama, an interior ministry statement said. Earlier this week, hundreds of protesters marched carrying banners calling for a boycott and a demonstration was held near Bahrain's international airport as the teams began arriving, despite the arrest of about 80 leading democracy activists. The Bahrain Grand Prix was cancelled last year in the wake of a Shiite-led uprising against the Sunni monarchy and the brutal government crackdown that followed in which a government commission said 35 people were killed.