Hyderabad: Communal violence broke out in Sangareddy town of Andhra Pradesh, forcing the police to clamp indefinite curfew.

Twenty people were injured and several shops were set afire in the large scale violence late Thursday night in Sangareddy town of Medak district, about 70 km from here.

The police on Friday said the situation was peaceful but tense. A police officer said patrolling has been intensified in the sensitive areas and the curfew was continuing as a precautionary measure.

The violence broke out Thursday night when a youth allegedly posted on Facebook a provocative photograph of a place of worship. Even as a group of people was staging a protest outside police station demanding his arrest, a mob started attacks on shops and vehicles at Old Bus Stand.

The rampaging mob set afire 40 shops, two four-wheelers and four auto rickshaws. It also looted several other shops and small road-side kiosks. A police vehicle was also torched.

The looting and attacks continued till 1 a.m. Locals alleged that the police remained mute spectator.

As many as 20 people including few policemen were also injured in the stone pelting by two groups.

Police had called additional forces from other parts of the district. As a precautionary measure, security had been tightened in other towns and districts.