Thousands of opposition protesters took to the streets of Bahrain on Friday to push their demands for political change two days before a Formula One car race that puts the kingdom in the global spotlight.
The atmosphere was mostly peaceful as groups of men, women and children carrying Bahraini flags walked down a highway towards the rallying point.
But a handful of youths in Duraz village temporarily blocked a highway with burning tyres, sending black smoke into the air.
Police cleared the tyres to allow traffic through. Wood, sticks and bricks blocked another street nearby, witnesses said.
Anti-government protesters and security forces also clashed overnight, with the demonstrators setting tyres ablaze on roads and police firing tear gas and stun grenades, the BBC reported.
Opposition activist Ala'a Shehabi told Reuters she believed unrest took place in about 10 to 15 Shi'ite villages overnight but she could give no other details.
Many in the Shi'ite Muslim majority Gulf Arab state accuse the Sunni-led government of trying to use Sunday's race to paper over human rights abuses and disguise political problems they say still plague the country, a close U.S. ally.