The explosion occurred while a team of CAF was patrolling near Dharampenta village under Kistaram police station limits to ensure security of an under construction culvert, Sukma Superintendent of Police D Shrawan told PTI.
When the security forces were cordoning off the construction site, located nearly 450 kms away from here on Konta-Kistaram route in the extreme south Bastar, naxals triggered the explosion, leaving two jawans injured, he said.
Soon after the incident, the jawans were rushed to a local health centre, he said.
Meanwhile, a combing operation has been launched in the region to nab the attackers.
The Home Minister will arrive at Raipur tomorrow afternoon for his two-day visit to Chhattisgarh.
During the tour, Singh will also visit Sukma to inaugurate a newly built fortified police station at Dornapal.