Police said today that Maoists had planted the explosive to target security men.
Inspector General of Police (south-western range) Y K Jethwa said the blast was heard from Balipeta area, around 90 km from here, last evening after a team of security personnel had crossed the spot.
"Few minutes after a vehicle carrying our forces passed the crime spot, the explosive went off. There is no report of any injury or casualty," Jethwa said, adding going by preliminary report it was a blast of lesser intensity.