Thousands of Bahrainis have demonstrated near the capital, Manama, urging democratic reforms, part of a series of protests planned by the political opposition ahead of next week's Formula One Grand Prix.
Under the banner "Democracy is our right," the crowds marched in the Shia area of Aali south of the capital, waving Bahraini flags and chanting anti-monarchy slogans on Friday.
Police stayed away from Friday's demonstration as protesters denounced king Hamad bin Issa al-Khalifa and Prime Minister Sheikh Khalifa bin Salman al-Khalifa, his uncle.
"You have no legitimacy," they chanted.
Bahrain's mainly-Shia opposition bloc, Al-Wefaq, organised the protest as part of demonstrations due to take place from April 12-22 to coincide with the April 19-22 Grand Prix.
Sheikh Ali Salman, head of the Al-Wefaq who was at the protest, said the action was intended to support "demands for democratic transition".
"We do not want to hold up the race, but we are trying to benefit from the increased media presence," he said.
Salman called on his supporters to attend a demonstration planned for April 19, as the event kicks off on the Sakhir circuit south of the capital.
A second opposition group, the February 14 Movement, organised another protest on Thursday night in the village of Khamis that was broken up by police.
Thursday night's demonstration came as a report by Human Rights Watch said that police have been rounding up pro-democracy activists in bid to head off protests.
'Your race is a crime'
"Your race is a crime," the protesters chanted, referring to motor racing bosses who have insisted on keeping the Bahrain Grand Prix on the Formula One calendar, witnesses said.
"Down with Hamad," they shouted in reference to the king, who heads a Sunni minority regime in the Shia-majority island state.
"The people want the fall of the regime," the demonstrators chanted, echoing the rallying cry of the Arab Spring revolts in 2011.
Clashes erupted when anti-riot police intervened to disperse the crowd and demonstrators responded with Molotov cocktails, witnesses said.
Bahrain, where the US Navy's Fifth Fleet is based, was rocked by month-long pro-democracy protests led by the kingdom's Shia majority in early 2011 that were crushed with the help of Saudi-led GCC troops.
Human rights groups say a total of 80 people have been killed since February 2011.
Last year's Formula One event went ahead against an ugly backdrop as police responded to protesters who were throwing petrol bombs by using tear gas, sound bombs and birdshot.
Meanwhile, former world champion Damon Hill has called on International Motoring Federation (FIA) president Jean Todt to take an ethical stance on the controversial event.
"I think Jean's approach is say nothing because otherwise you are being political," said Hill, who won the world title in 1996.
"I think that is a mistake because actually he is being political because he's being used, or the sport is perceived as being used, by its engagement in the economy and the reputation of the country."