Shots rang out in the Bahraini capital of Manama on Friday when anti-government protesters approached a central square from which they had been forcibly rousted a day earlier, news agencies in Manama reported.

Two groups of marchers had started to merge at the Pearl Square roundabout when shots were fired by soldiers, CNN reported, quoting witnesses at the scene. The network said the wailing of arriving ambulance sirens could also be heard.

The shots heard from the protest venue were tear gas and soldiers firing heavy weapons into the air, the Associated Press reported.

Pearl Square was the scene of a bloody crackdown early Thursday when government troops swept through an encampment of sleeping protesters. At least four died in the melee that cleared the protest site. Bahraini officials had warned that all necessary measures would be taken to prevent the Persian Gulf state from being pushed over "the brink of the sectarian abyss."

While other Middle East unrest has targeted long-reigning leaders for political failures, the protests in Bahrain have given voice to Shiite Muslim discontent under the Sunni royal family that holds power in the tiny Gulf state.

Bahrain is home to the U.S. 5th Fleet and a strategic defensive point for protecting oil traffic through the Strait of Hormuz. U.S. Secretary of State Hillary Rodham Clinton on Thursday told her Bahraini counterpart that the government should renounce the use of force against the demonstrators and heed legitimate calls for democratic reform.

-- Carol J. Williams

Photo: Bahraini anti-government demonstrators run during Friday clashes in Manama between protesters and the army. Credit: Associated Press