Violence broke out on Monday as crowds of Muslims protested against attempts to erect a statue of the Hindu goddess Durga on a disputed piece of land.
Police opened fire on several occasions and one civilian was killed, while seven people, including four policemen, were injured in clashes with stone-throwing protestors.
The home secretary of Bihar state, U.N. Panjiyar, told AFP that two army companies, together with six companies of paramilitary police had been deployed in the area to enforce the curfew and restore order.
A total of 55 people have been arrestd.
Tension gripped Biharsharif, some 60 kilometers (40 miles) east of the Bihar state capital Patna, several days ago, when police seized a Durga idol in an attempt to avert Hindu-Muslim clashes.
The situation turned critical on Sunday when some Hindus attempted to install another Durga idol on a stretch of land that has been under dispute since 1993.