Indian police in the south Indian city of Hyderabad are maintaining a tight vigil after paramilitary forces trying to break up clashes between two religious communities killed three people.
The violence broke out on Wednesday in the old quarter of the capital city of Andhra Pradesh, which has a mixed Hindu-Muslim population, according to AFP news agency.
Hyderabad police have declined to say who or which communities were involved in the rioting.
Trouble erupted after some people attacked houses and shops of a religious minority following rumours that a religious flag had been burnt.
Security forces placed a curfew on the area and the situation was under control, CV Anand, Hyderabad police commissioner, said.
Police initially tried to break up the mob using sticks but then had to "open fire to disperse the clashing groups", Anand said.
The Press Trust of India news agency said at least three people died of bullet wounds after reaching the hospital.
Extra police and paramilitary forces were rushed to the area as shopkeepers around Hyderabad's historic Charminar monument pulled down shutters for fear of more violence.
The violence comes as India awaits the result on Friday of its general election. Exit polls, which have been unreliable in the past, indicate that the opposition Bharatiya Janata Party (BJP) led by Narendra Modi will to sweep to power.
Political analysts have voiced fears that a victory for the BJP, with its close association with Hindu nationalist identity, could stir religious tensions in multi-religious India.