Pro-democracy protesters burned tire barricades in Bahrain's capital today as the Formula One Grand Prix went ahead without disruption several kilometres away, protected by layers of security forces.

Security officials remained on high alert amid fears that activists would follow through with a threat to disrupt the event, which was won without incident by two-time world champion Sebastian Vettel.

Last year's Bahrain Grand Prix was cancelled as a result of the uprising against the country's hardline rulers. At least 50 people have been killed in anti-government unrest that began last February.

Opposition activist Sayed Ahmed said protesters want to use the race to focus international attention on their demands for political reform. He said human rights should be a priority over a sporting event.

si-bahrain-tear-gas-300-rtr311di

Demonstrators run through a cloud of tear gas fired by police during a protest in the village of Diraz, west of Manama on Saturday. (Hamad I Mohammed/Reuters )

The discovery of a protester leader's body near the scene of Friday night's violence between police and protesters threatens to tip Bahrain deeper into unrest. The body of Salah Abbas Habib Musa, 36, was found Saturday on a rooftop in the opposition stronghold of Diraz, west of the capital, Manama.

The heavily guarded Bahrain International Circuit, where the F1 is taking place in the desert, is about 20 kilometres from Diraz.

The interior ministry said the case was "being treated as a homicide." It did not give a cause of death but said investigators found "a wound" on the left side of Musa's body. Authorities have opened an investigation into his death, apparently in a bid to defuse tensions.

Opposition leaders claimed Musa was targeted by the security forces because he was a prominent activist in the opposition movement in Bahrain, an island nation that is home to the U.S. Navy's 5th Fleet.

During Saturday's protest in Diraz, police fired dozens of rounds of tear gas at protesters.

"The authorities have reportedly put armoured personnel carirers on the roads leading to the site, and we're told that they're armed with pump-action shotguns as well," freelance journalist Dominic Valitis told CBC News, reporting from London.

Race drivers have mostly kept quiet about the controversy surrounding the Bahrain Grand Prix.

Asked about Musa's death after taking pole position in Saturday's qualifier, F1 world champion Sebastian Vettel said, "I think it's always dreadful if someone dies."

Bahrain's monarchy is the main backer of the F1 race, and the crown prince owns rights to the event.

Bahrain was the first Middle Eastern country to welcome F1 in 2004. Members of the ruling Al Khalifa dynasty are huge fans of the sport and the country's sovereign wealth fund, Mumtalakat, owns 50 per cent of leading team McLaren.

Bahrain's leaders lobbied hard to hold this year's event in efforts to portray stability and mend the country's international image despite almost daily and increasingly violent confrontations between security forces and protesters.

With files from The Associated Press