There are growing fears the crackdown by Bahrain’s Sunni royal family against demonstrators from its Shi’ite majority could trigger conflict further afield.

Bahraini forces used tanks and helicopters to drive mainly Shi’ite protesters from the streets of the capital El Manama.

A camp occupied by anti-government activists for weeks was cleared. At least three civilians and three police were said to have been killed in clashes.

The assault began less than 24 hours after Bahrain declared martial law. It had brought in troops from fellow Sunni-ruled neighbours like Saudi Arabia.

But Saudi Shi’ites have reportedly been protesting in support of their Bahraini brethren. Iran’s President Mahmoud Ahmadinejad said Bahrain’s crackdown was “unjustifiable and irreparable.” And Iraq’s Shi’ite community has been galvanised, exacerbating sectarian tensions that led to years of war in the country.