Formula One drivers will race in Bahrain while protesters outside the complex denounce the Grand Prix as a gaudy spectacle by a ruling family that crushed Arab Spring demonstrations last year.
Demonstrators hurling petrol bombs have clashed nightly with police during the past week, and security forces responded with teargas, rubber bullets and birdshot.
The death of protester Salah Abbas Habib, 36, found on a rooftop after overnight clashes, has provided more fuel for outrage among a Shi'ite Muslim majority that complains of being marginalised by ruling Sunnis.
His funeral could be held on Sunday if his family recovers his body, setting the stage for riots on race day.
The luxury sporting event is the government's chance to prove that life has gone back to normal in the island kingdom after security concerns over anti-government demonstrations forced last year's race to be cancelled.
King Hamad bin Isa al-Khalifa, who will attend Sunday's race, said in a statement overnight that he wanted to make clear my personal commitment to reform and reconciliation in our great country. The door is always open for sincere dialogue amongst all our people.
Bahrain, a close military ally of the United States, is the only one of the Gulf monarchies to have been seriously threatened by Arab Spring protests that brought down the rulers of Tunisia, Egypt, Libya and Yemen since the start of 2011.
Our initial demands were to elect a new government but after the disgusting abuse we received, all the people are asking for is for the regime to fall, said protester Ahmed Madani during a march of 7000 people on Saturday.
Some banners held up during the march depicted Formula One race car drivers as riot police beating up protesters.