Some militant outfits in Uttar Pradesh, which had links with the outlawed Students' Islamic Movement of India, had a hand in Wednesday's disturbances in Kolkata, said the state government.
Intelligence sources in Kolkata said that there was prior information that Islamic militants from Uttar Pradesh, earlier connected with the SIMI, were inciting minorities in some areas of central Kolkata.
The sources said it was a carefully planned operation.
Kolkata police chief Gautam Mohan Charkbaorty pleaded ignorance about the involvement of Islamic militant outfits but a senior officer in the Kolkata Police admitted that outsiders instigated the violence.
Home Secretary P R Roy said that investigations were on into the violence and steps would be taken against the perpetrators.
Asked whether any magisterial inquiry would be ordered into the violence, he said the police had magisterial power.