Police carried out raids in Panur and surrounding areas on Friday in the wake of the bomb blast at Parad in Kunnothuparamba panchayat on Thursday around 8.45 pm.
North Zone ADGP Shanker Reddy visited the site and evaluated the situation.
According to Kolavellur SI E V Fayis Ali, the police team led by SP Rahul R Nair conducted detailed search operations at the blast site in Parad in which seven youths, allegedly connected with the NDF, were injured.
Four of them have been admitted to various hospitals in Thalassery and Kozhikode. At least two victims have lost their palms and sustained serious burns on their face.
Fayis Ali said that preliminary investigations showed that the blast occurred when the youths were engaged in bomb-making.
Six live steel bombs and six empty steel cases for filling the ammunition were found from the area.
Police suspect that the gang was trying to fill gunpowder in the steel cases when the explosion took place.
According to sources, crude steel bomb-making was rampant in the area and the explosives were often transported to different parts of the district, to Kozhikode and even to Karnataka.
The bomb-makers used gunpowder taken out from common crackers and mixed glass and nails to make the explosive more lethal.