"There has been an escalation of criminal activity towards RBM employees and one was shot and seriously injured in the last few days," Rio said in a statement.
The company said all mining operations have been halted and the smelters are operating at a reduced level, with a minimum number of employees now on site.
(This story corrects acronym to 'RBM' from 'RMB' in paragraph one)
(Reporting by Niyati Shetty in Bengaluru; Editing by Chris Reese)