Manama:
Thousands of anti-government demonstrators cut off Bahrain's financial centre and drove back police trying to push them from the capital's central square, shaking the tiny island kingdom on Sunday with the most disruptive protests since calls for more freedom erupted a month ago.
Riot police fired tear gas and rubber bullets at anti-government demonstrators blocking the highway into Manama's financial district and surrounded the protesters' main camp in the capital, eyewitnesses said.
The government said security forces dispersed about 350 protesters using tear gas, but eyewitnesses said police failed to dislodge the thousands of protesters blocking the highway.
Thousands of protesters had gathered before dawn to block King Faisal Highway, a four-lane expressway leading to the financial district.
They caused huge traffic chaos during morning rush hour and prevented many from reaching their offices on the first day of the working week.
Traffic was clogged until late morning and many drivers sent messages of rage and frustration to social media sites.
Demonstrators also clashed with security forces and government supporters on the campus of the main university.
About two miles (three kilometres) away, police at the same time moved in on Pearl Square, site of a month long occupation by members of Bahrain's Shiite majority calling for an elected government and equality with Bahrain's Sunnis.
Two protesters sustained serious head injures during Sunday's clashes and hundreds looked for medical help, mostly with breathing problems from tear gas, hospital officials said.
The clashes fuelled fears that Bahrain's political crisis could be stumbling toward open sectarian conflict between the ruling minority Sunnis and Shiites, who account for 70 percent of the nation's 525-thousand people.
Many protesters in recent days have pressed their demands further to call for the ouster of the Sunni dynasty that has held power for more than two centuries.