A PTI correspondent saw 200-odd CPI-M activists proceeding to Sonachura from Bhangaberia near Khejuri, apparently to take "control" of the area, which was a party stronghold.

The activists fired their rifles and exploded bombs. From the opposite side, members of the Bhumi Uchhed Pratirodh Committee headed for Sonachura in a procession that was peaceful.

Marxists who were checking buses and other vehicles detained five reporters covering the CPI-M procession, including the PTI correspondent, at Hanschara bus stop near Khejuri. They were later released.

Superintendent of Police Ashok Kumar Dutta, when asked by journalists to comment on the incident, said police had nothing to do with them.

Police had not entered the troubled areas since January 6. Inspector General of Police (law and order) Raj Kanojia said in Kolkata that he had no information on the developments.

The Nandigram block has witnessed violence since early January over the acquisition of farmland to set up a special economic zone.