Armed activists of a splinter group of CPI(Maoist) - Azad Hind Fouj - vandalised a brick kiln at Simraha Chatarbhuj village early on Sunday and threatened its owner with dire consequences if he refused to meet their extortion demand.

A total of 22 members of the group, formed in north Bihar last year, stormed into the kiln, around 15km from Muzaffarpur, with firearms around 1.30am. They set ablaze two tractors and an earth remover machine, ransacked bricks of the kiln under the jurisdiction of Ahiyapur police station and assaulted its caretakers - Ritu Kumar and Shiv Chandra Paswan.

In the absence of the kiln owner Rajiv Ranjan, the rebels pasted pamphlets, asking the owner to stop spying for the police and provide extortion money or face the consequences.

Later, the rebels sprayed bullets in the air and fled towards the bordering areas of the Sheohar district under the cover of darkness.

Senior superintendent of police Ranjit Kumar Mishra, along with deputy commandant of Sashastra Seema Bal (SSB) and heavy police reinforcement, rushed to the spot to take stock of the situation.