District Collector Sandeep Nanduri along with other officials seal the main gate of the Sterlite copper unit, on Monday. Pic/PTI

The violent protests and police firing in Tuticorin that claimed 13 lives rocked the Tamil Nadu assembly on Tuesday with Chief Minister K Palaniswami maintaining that police action was "unavoidable" even as the main Opposition DMK staged a walked out over the issue. On the violent incidents that occurred on May 22 in Tuticorin, Palaniswami said measures like teargas and baton-charge were used against those who indulged in violence.