The police today cracked down on anti-Posco agitators, mostly women and children, at Balitutha, the entry point to proposed plant site, firing teargas shells and rubber bullets to disperse them, injuring at least 20 people.

The security personel ordered the around 1,000 agitators of the CPI-backed Posco Pratirodh Sangram Samiti (PPSS), on dharna since January 26, to disperse immediately from the area where prohibitory orders were clamped, police said.

The security personnel took action when activists of the PPSS threw crude bombs at them, they said.

At least 20 agitators were injured when the police fired rubber bullets and teargas shells, they added.

Prohibitory orders were clamped around Balitutha and around 1500 policemen deployed as part of Orissa government's efforts to begin forest survey and land acquisition at the plant site.

"No one should indulge in violence," chief minister Naveen Patnaik told reporters in Bhubaneswar.

Stating that the government believed in peaceful industrialisation, Patnaik said the district administration of Jagatsinghpur was negotiating with the agitators to clear road which had been captured by them since January 26.

Meanwhile, CPI MP from Jagatsinghpur Bibhu Prasad Tarai, Congress leader Umesh Swain and Jayant Biswal were arrested en route to protest site.

Justifying Tarai's arrest, agriculture minister and BJD leader Damodar Rout, said anyone obstructing government officials in performing their duties should be booked.

"Be it an MP, MLA or minister, everyone should abide by the law," Rout said.

Top leaders of PPSS including Abhay Sahu and Sisir Mohapatra, the local Sarpanch, who had reached the dharna site, appeared to have gone underground to avoid arrest.