Nervous shop owners closed their doors and security forces fanned out across Bahrain's capital Thursday in attempts to quell widening unrest that threatened to overshadow the return of the Formula One Grand Prix to the Gulf kingdom.
Sporadic clashes, including riot police firing tear gas and stun grenades at protesters, broke out even as authorities tried to present a sense of stability before Sunday's race. Bahrain called off the competition last year amid unrest in a sharp blow to the country's Sunni rulers, who are facing an uprising by the island nation's Shiite majority.
Two members of one of the F1 teams, Force India, decided to leave Bahrain after a team vehicle was caught in a traffic jam Wednesday because of a hurled firebomb. The lockdown atmosphere in parts of the capital, Manama, also spread to key tourist districts, including the main gold market, which normally would be bustling with visitors in town for the F1.
Most shops in the gold market were shuttered and stores in other shopping areas closed early because of fears of clashes spilling into the narrow streets. Police helicopters buzzed over parts of the city.
In one protest march, hundreds of people _ some chanting slogans against the Formula One _ clashed with security forces firing tear gas and stun grenades. The demonstrators also held aloft banners for a jailed activist, Abdulhadi al-Khawaja, who has been on a hunger strike for more than two months.
Nearly 50 people have been killed since February 2011 in violence between security forces and protesters from Bahrain's Shiite majority, which seeks to break the near monopoly on power by the island nation's Sunni monarchy.
Shiites account for about 70 percent of Bahrain's population, but claim they face widespread discrimination and are blocked from key political or military posts in the strategic kingdom, which is home to the U.S. Navy's 5th Fleet. The Sunni leaders have offered some reforms, but the opposition says they fall short of their demands.
On Wednesday, protests disrupted a cultural exhibition set up as part of Formula One events. On the track, teams will be practicing Friday and Saturday before qualifying later Saturday. The race is scheduled for Sunday.
A statement by Bahrain's chief of public security, Maj. Gen. Tariq al-Hassan, said that "a number" of suspects have been arrested in recent days on charges that include taking part in "illegal rallies and gatherings" and using firebombs and iron rods in attacks.
He vowed "zero tolerance" for violent protests.
A rights group, Bahrain Watch, accused security forces of using excessive measures by firing birdshot pellets against demonstrators.