Seeking to know whether the Andhra Pradesh Task Force personnel acted with adequate restraint on red sander smugglers, 20 of whom were killed, Tamil Nadu Chief Minister O Panneerselvam today shot off a letter to his Andhra Pradesh counterpart Chandrababu Naidu seeking a "credible and speedy enquiry" into the matter.

Many of those killed hailed from Tamil Nadu with some suspected to be labourers.

"I am very distressed to learn that in an operation conducted early this morning by the Red Sanders Anti-Smuggling Task Force personnel of Andhra Pradesh in the Srivarimettu and Eesagunda areas in Seshachala forest area, about 20 persons sustained bullet injuries and succumbed to the injuries on the spot," Panneerselvam said in his letter.

"Many of these persons are reportedly from Tiruvannamalai and Vellore districts of Tamil Nadu," he said.

"While it is possible that these persons may have been engaged in illegal activities, the occurrence of such high casualties in the operation raises concerns whether the Task Force personnel acted with adequate restraint," he said. Even if a person was engaged in illicit tree cutting, Panneerselvam said "efforts could have been made to apprehend them rather than take such drastic action and cause such high casualties".