* Protesters block roads, police fire teargas -activist
* Youth have clashed with security almost every night
* Crown prince urges a "focus on what's positive"
Bahraini pro-democracy activists reported sporadic clashes between police and protesters on Sunday, hours before a Formula One race promoted by the government as a non-political festival of sport but seen by the opposition as a public relations stunt.
Some protesters blocked roads around the capital Manama on Sunday morning and police fired teargas at a secondary school in the city where students had been demonstrating, Sayed Yousif al-Muhafda of the Bahrain Centre for Human Rights said.
Scores of police cars and a couple of armoured vehicles stood along the highway from the capital to the race circuit.
Asked for comment on the reported clashes, which included more of the near-nightly violence between police and youths, in villages near the capital, an interior ministry official said only that everything was normal.
Protests in the Gulf Arab country - a key Western ally that hosts the U.S. Navy's Fifth Fleet - broke out in 2011, with the Shi'ite-led opposition drawing thousands of demonstrators demanding democratic reforms from the Sunni-led government.
Bahrain's Crown Prince Salman al-Khalifa dismissed the suggestion the government was using the race to paper over human rights abuses. He said more than 15,000 people visited the circuit on Friday and more were expected on Sunday.
"What I would like to say is let's focus on what's positive, let's build upon the platform that we have, and let's celebrate this event with Bahrainis who are really passionate," he told reporters on Saturday at the Sakhir desert circuit, roughly 30 km (19 miles) southwest of the capital Manama.
Crown Prince Salman is a driving force behind talks between the government and main opposition groups aimed at breaking the political deadlock. He described the race as an opportunity to transcend national differences.
On Saturday, protests broke out in about 20 villages, human rights activists said, with protesters throwing rocks at police and security forces responding with tear gas in many cases.
CALM AT THE TRACKS
Muhafda said he documented six shotgun injuries during clashes in the village of Jidhafs, and two cases of protesters beaten by police in the Sanabis area west of Manama on Saturday.
He said protests also broke out in other villages near the capital, where the Pearl Roundabout, a centre of the 2011 uprising, has since been razed.
"There were many injuries and many attacks by teargas," he said by telephone, adding he expected more protests on Sunday.
Reuters could not independently verify most of the reports.
Chief of Public Security Major-General Tariq Al Hassan said on Saturday his forces would deal firmly with any illegal activities, an interior ministry statement said.
"Security forces have been deployed around the circuit and patrol the area regularly, and police have been deployed along all highways leading to the event's venue for security purpose and to facilitate traffic," the statement quoted him as saying.
The government denies carrying out arbitrary arrests and torture and says any reports of wrongdoing by its security forces are investigated.
In contrast to the Shi'ite-inhabited villages where clashes regularly take place, there was little evidence of unrest in downtown Manama or around the race track itself.
Spectators there on Sunday enjoyed a carnival atmosphere, watching music and dance performances and other activities geared towards children.
Watched by millions around the world, the opposition has hoped to use the race to put the spotlight on its pro-democracy campaign. The government has hoped to show unity and has portrayed the protesters as trying to undermine Bahrain's international image.
"This weekend is really about sport," Salman said.