Manama - Bahrain's opposition on Saturday reported the first death in protests timed for this weekend's controversial Grand Prix as the kingdom imposed a security lock-down around the Sakhir Formula One racing circuit.
The body of Salah Abbas Habib, 36, was found in Shakhura village, where security forces overnight "attacked peaceful protesters, brutally beating some of them with various tools and weapons," said Al-Wefaq, the Gulf state's largest Shi'ite opposition bloc Al-Wefaq.
It charged that "security forces killed him one day before the final round of the F1 races hosted by Bahrain," without saying how he died.
In a statement on social networking website Twitter, the interior ministry confirmed that "the body of a deceased person was found in Shakhura today".
It added that police have begun an investigation" into the death, which is being considered a homicide.
One of Saleh's relatives told AFP he "was taking part in the protest in Shakhura on Friday and was arrested by security forces while other protesters managed to flee."
The family member said there had been no word of him after the protest "until we were told that his body was found on Saturday morning".
Witnesses told AFP security forces fired tear gas and sound bombs to disperse dozens of people who gathered in the area where Habib's body was found.
Dozens of armoured vehicles were deployed on Saturday on roads leading to the circuit, where Sunday's race is going ahead despite calls by rights groups to cancel the event because of rising political tensions in Bahrain.
Security gates were set up and bags thoroughly searched at entrances to the circuit.
Activists said a protest was planned for later on Saturday at the Shi'ite village of Darraz, 10km north of Sakhir, followed by a march towards the track.
Late on Friday, protesters clashed with riot police in several Shi'ite villages, witnesses said, with security forces firing tear gas and sound bombs to disperse demonstrators, some of whom hurled petrol bombs and stones.
The clashes followed a massive afternoon demonstration in the Shi'ite suburb of Budaya, west of Manama.
Officials insisted the event was safe, although Force India team withdrew from Friday afternoon practice on safety grounds, two days after four of its mechanics were caught up in traffic near an exploding petrol bomb.
Force India deputy team principal Bob Fernley said Wednesday's incident had "destabilised the emotional element of our team," but insisted they supported the Grand Prix and were fully committed to the event.
Two of his team members chose to leave Bahrain on Thursday.
"I think cancelling just empowers extremists," Bahraini Crown Prince Salman bin Hamad Al-Khalifa said on Friday.
"I think for those of us who are trying to navigate a way out of this political problem having the race allows us to build bridges across communities," he told media at Sakhir.
Jean Todt, president of F1 ruling body the International Motoring Federation (FIA), said he did not believe the sport's image would suffer because of criticism over the event going ahead.
Days of rage
The Frenchman told reporters at Sakhir on Saturday that he felt F1 had made the right decision.
"The sport has to be healing any kind of problem in the world," he said. "We are not a political body, we are a sporting body. I already hope it will be a great outcome to hold the Grand Prix."
Shiite-led protests have intensified in Bahrain, site of a month-long uprising that was crushed last year, since the ruling Sunni dynasty in the Shi'ite-majority nation insisted on going ahead with the Grand Prix.
The February 14 Youth Movement called on social networking sites for "three days of rage" coinciding with the race.
Al-Wefaq had called for a week of daily protests during the event to focus media attention on their long-standing demands for reforms.
The head of the Bahrain Youth Society for Human Rights, Mohammed Maskati, has said the protests were "a message to those taking part in the F1 race to bring their attention to human rights violations in Bahrain."
Defending double world champion Sebastian Vettel of Red Bull took his first pole position of 2012 after coming top in Saturday's qualifying.
Vettel outpaced McLaren's Lewis Hamilton by just 0.098 seconds, while the second Red Bull of Mark Webber and Hamilton's teammate Jenson Button will start on the second row.