Around one hundred anti-government protesters threw stones and petrol bombs as riot police tried to disperse them with tear gas and stun grenades in Bahrain on Friday, witnesses said, after an earlier demonstration attended by thousands passed peacefully, Reuters reported

At least two protesters were injured in the clashes, the witnesses said, which took place after a march near the capital Manama, which had been called for by main opposition bloc al-Wefaq and was authorized by the Bahraini authorities.

Bahrain, headquarters of the U.S. Navy's Fifth Fleet, has been in turmoil since pro-democracy protests led by its Shi'ite Muslim majority erupted last year and were put down by the Sunni rulers.

The ruling Al Khalifa family used martial law and help from Gulf neighbors to put down last year's uprising, but unrest has resumed.

Bahraini authorities accuse regional Shi'ite power Iran of encouraging the unrest and has vowed a tough response to violent protests as talks with the opposition have stalled.