A group of Maoists swooped down on a bridge construction site of a private firm at Dudhiyatadi village in Banka late on Sunday night and assaulted several labourers after they failed to find their target - the cashier of the company.

The rebels fired indiscriminately in the air and torched vehicles parked at the site, around 270km southeast of Patna. Sources said non-fulfilment of levy demand triggered the Naxalites' attack on the bridge construction site of Chaubatiya Construction.

The Banka firm has been assigned the job of constructing a road bridge across the Orni, a tributary of the Chandan, connecting Dudhiyatadi to Pindoran village.

Rajendar Yadav, the proprietor, said the rebels had demanded money earlier. "But we did not take the matter seriously," he said.

Banka superintendent of police Satya Prakash said the firm owner had never informed the police about any monetary demand of Naxalites. The officer said nine labourers were injured in the attack. Of them, three suffered bullet injuries.

"Around 20 to 22 Maoists arrived at the site, searching for a particular official of the company. When they could not find him, they assaulted those present at the site," he said.

Eyewitnesses said the rebels attacked the site around midnight. "We woke up to the sound of gunshots. The rebels were looking for the accountant of the firm. When we tried to escape, they fired at us. I suffered a bullet injury in my hand," said Madan Rai, a worker in the company.

Rai, along with eight other employees, has been admitted to Banka sadar hospital.

The rebels torched a sports utility vehicle, a tractor, an excavator, an earthmover and a motorcycle parked at the base camp of the firm.

Joint raid on rebels

Chandrika Sah, an alleged Maoist, was nabbed in a joint raid conducted by the CoBRA battalion of CRPF and East Champaran police at Rajepur village in the early hours on Monday. Additional superintendent of police (operation) Rajiv Kumar was among the officers involved in the operation.