Authorities have imposed a curfew on a key border city in southern Nepal after Hindu and Muslim groups began protesting against each other. Officials say the unrest followed the vandalism of a mosque over the weekend. The Parsa District Administration on Tuesday issued curfew orders banning street gatherings and demonstrations. The notice warns violators could be shot by security forces. Armed soldiers and police were patrolling the streets of Birgunj, a crucial border point for imports from India. Although there have been no major clashes, minor scuffles with riot police were reported. Clashes between Hindus and Muslims are rare in Nepal.