R Prasanna, the district collector, told PTI that Agnivesh and others were heading for Tadmetla when they faced the protesting Salwa Judum activists in Doranpal village.
Salwa Judum activists, including a large number of women, allegedly threw eggs and tomatoes at their vehicles, he said.
Agnivesh and others were unhurt and they had been provided with security, he said. Agnivesh later issued a statement, saying that he did not blame the villagers for the incident, as they too had been victims of violence, and he had sympathy for them.
Fire had broken out at Tadmetla on March 12, in which houses were gutted, and local tribal community alleged that security forces were behind it.