At least two people have been killed in riots across the Indian state of Punjab.It comes after a Sikh guru was murdered on Sunday by a rival group in Austria. Thousands of angry protesters took to the streets of the Indian state as news of the death spread. Authorities imposed a curfew and the army was put on standby after members, mainly of the Dalit or “untouchable” caste, went on the rampage, torching a train, vehicles and shops. The Indian Prime Minister has appealed for calm. 57-year-old Guru Sant Rama Nand died after armed men attacked the preacher and worshippers with a gun and knives in the temple in the Austrian capital. At least nine people were wounded; one is said to be critically ill. Local reports said the Guru had travelled from India to Vienna to conduct the service even though high-caste members of rival temples had threatened violence if he appeared.