Four policemen and three workers were hospitalised after suffering minor injuries.

Local media said the protesters included Indian, Pakistani, Bangladeshi and Afghan labourers employed by a building firm called Tiger Contracting.

While low wages was not confirmed as the sole reason for the protests, a labour ministry official said the company had increased monthly wages in February from $204 to $231.

Many construction workers in the Gulf region often complain of poor working and living conditions.

They have also been hit hard by the weakening of the US dollar - to which the majority of Gulf currencies are pegged - which in effect reduces the value of the money they send back to their home countries.